tag:blogger.com,1999:blog-17823743343656102042024-02-19T06:55:13.675-08:00The World of OPTOPT is a telescope and camera store in San Diego County, California, and our website, OPTTelescopes.com, is one of the most trusted online astronomy stores in the world. We've been around since 1947, and our employees are involved in various aspects of astronomy...from professional quality CCD imaging to writing books on what's up in the sky. We've got a lot to share, and this is where we will share it! Welcome!OPT Telescopeshttp://www.blogger.com/profile/03110540494737772047noreply@blogger.comBlogger164125tag:blogger.com,1999:blog-1782374334365610204.post-77819360681329528762012-09-09T12:39:00.001-07:002012-09-09T12:40:40.393-07:00Weekly SkyWatcher's Forecast: September 10-16, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! With very little Moon to contend with this week, it will be a great time to take on some challenging studies like the Helix Nebula, Saturn Nebula, Stephen's Quintet and more. It's time to get out your big telescope and head for some dark skies... Because this week isn't for the beginner! Whenever you're ready, I'll see you out back... <a name='more'></a>
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<b>Monday, September 10</b> – Today is the birthday of James E. Keeler. Born in 1857, the American Keeler was a pioneer in the field of spectroscopy and astrophysics. In 1895, Keeler proved that different areas in Saturn’s rings rotate at different velocities. This clearly showed that Saturn’s rings were not solid, but were instead a collection of smaller particles in independent orbits.
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Now, let’s head on to Capricornus and drop about four finger-widths south of its northeastern most star – Delta – and have a look at M30 (Right Ascension: 21 : 40.4 - Declination: -23 : 11). Discovered in 1764 by Charles Messier, binocular observers will spot this small, but attractive, globular cluster easily in the same field with star 41. For telescopic observers, you will find a dense core region and many chains of resolvable stars in this 40,000 light year distant object. Power up!
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Let’s get some more practice in Capricornus, and take on a more challenging target with confidence. Locate the centermost bright star in the northern half of the constellation – Theta – because we’re headed for the “Saturn Nebula”.
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Three finger-widths north of Theta you will see dimmer Nu, and only one finger-width west is NGC 7009 (Right Ascension: 21 : 04.2 - Declination: -11 : 22). Nicknamed the “Saturn Nebula”, this wonderful blue planetary is around 8th magnitude and achievable in small scopes and large binoculars. Even at moderate magnification, you will see the elliptical shape which gave rise to its moniker. With larger scopes, those “ring like” projections become even clearer, making this challenging object well worth the hunt. You can do it!
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<b>Tuesday, September 11</b> –Today celebrates the birthday of Sir James Jeans. Born in 1877, English-born Jeans was an astronomical theoretician. During the beginning of the 20th century, Jeans worked out the fundamentals of the process of gravitational collapse. This was an important contribution to the understanding of the formation of solar systems, stars, and galaxies. <br><br>
So, are we ready to try for the “Helix”?
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Located in a sparsely populated area of the sky, this intriguing target is about a fist width due northwest of bright Formalhaut and about a fingerwidth west of Upsilon Aquarii. While the NGC 7293 (Right Ascension: 22 : 29.6 - Declination: -20 : 48) is also a planetary nebula, its entirely different than most… It’s a very large and more faded edition of the M57! On a clear, dark night it can be spotted with binoculars since it spans almost one quarter a degree of sky. Using a telescope, stay at lowest power and widest field, because it is so large. It you have an OIII filter, this faded “ring” becomes a braided treat!
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<b>Wednesday, September 12</b> – Today in 1959, the USSR’s Luna 2 scored a mark as it became the first manmade object to hit the moon. The successful mission landed in the Paulus Putredinus area. Today also celebrates the 1966 Gemini 11 launch.
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Tonight let’s take the time to hunt down an often overlooked globular cluster – M56. Located roughly midway between Beta Cygni and Gamma Lyrae (RA 19 15 35.50 Dec +30 11 04.2), this class X globular was discovered by Charles Messier in 1779 on the same night he discovered a comet, and was later resolved by Herschel. At magnitude 8 and small in size, it’s a tough call for a beginner with binoculars, but is a very fine telescopic object. With a general distance of 33,000 light-years, this globular resolves well with larger scopes, but doesn’t show as much more than a faint, round area with small aperture. However, the beauty of the chains of stars in the field makes it quite worth the visit!
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While you’re there, look carefully: M56 is one of the very few objects for which the photometry of its variable stars was studied strictly with amateur telescopes. While one bright variable star had been known previously to exist, up to a dozen more have recently been discovered. Of those, six had their variability periods determined using CCD photography and telescopes just like yours!
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<b>Thursday, September 13</b> – Today in 1922, the highest air temperature ever recorded at the surface of the Earth occurred. The measurement was taken in Libya and burned in at a blistering 136F (58C), but did you know that the temperatures in the sunlight on the Moon double that? If you thought the surface of the Moon was a bit too warm for comfort, then know surface temperatures on the closest planet to the Sun can reach up to 800F (427C) at the equator during the day! As odd as it may sound, even that close to the Sun – Mercury could very well have ice deposits hidden below the surface at its poles.
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Tonight we’ll move on to Aquila and look at the hot central star of an interesting planetary nebula – NGC 6804 (Right Ascension: 19 : 31.6 - Declination: +09 : 13). You’ll find it almost 4 degrees due west of Altair. Discovered by Herschel and classed as open cluster H VI.38, it wasn’t until Pease took a closer look that its planetary nature was discovered. Interacting with clouds of interstellar dust and gases, NGC 6804 is a planetary in decline, with its outer shell around magnitude 12 and the central star at about magnitude 13. While only larger telescopes will get a glimpse of the central, it’s one of the hottest objects in space – with temperatures around 30,000K!
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If that’s not “hot” enough for you, then take a look straight overhead at brilliant star Vega. It is a “Sirian type” star and with a surface temperature of about 9200 degrees Kelvin, it’s twice as hot as our own Sun. At around 27 light years away, our entire solar system is moving towards Vega at a speed of 12 miles per second, but don’t worry… It will take us another 450,000 years to get there. If we were to arrive tonight, we’d find that Vega is around 3 times larger than Sol and that it also has a 10th magnitude companion that can often be resolved in mid-sized scopes. It’s one of the first stars to ever be photographed. Back in 1850, that simple star – Vega – took and exposure time of 100 seconds through a 15″ scope. How times have changed!
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<b>Friday, September 14</b> – Tonight’s destination is not an easy one, but if you have a 6″ or larger scope, you’ll fall in love a first sight! Let’s head for Eta Pegasi and slightly more than 4 degrees north/northeast for NGC 7331 (Right Ascension: 22 : 37.1 - Declination: +34 : 25).
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This beautiful, 10th magnitude, tilted spiral galaxy is very much how our own Milky Way would appear if we could travel 50 million light years away and look back. Very similar in both structure to ourselves and the “Great Andromeda”, this particular galaxy gains more and more interest as scope size increases – yet it can be spotted with larger binoculars. At around 8″ in aperture, a bright core appears and the beginnings of wispy arms. In the 10″ to 12″ range, spiral patterns begin to emerge and with good seeing conditions, you can see “patchiness” in structure as nebulous areas are revealed and the western half is deeply outlined with a dark dustlane. But hang on… Because the best is yet to come!
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<b>Saturday, September 15</b> – In 1991 the Upper Atmosphere Research Satellite (UARS) was launched from Space Shuttle Discovery. The successful mission lasted well beyond its life expectancy – sending back critical information about our ever-changing environment. After 14 years and 78,000 orbits, UARS remains a scientific triumph.
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If you’re up early, why not check out Mars? While the red planet is visible, it’s also rather small at the moment, with an apparent diameter of less than .5”. Can you still spot some surface details?
Tonight return to the NGC 7331 with all the aperture you have. What we are about to look at is truly a challenge and requires dark skies, optimal position and excellent conditions. Now breathe the scope about one half a degree south/southwest and behold one of the most famous galaxy clusters in the night.
In 1877, French astronomer – Edouard Stephan was using the first telescope designed with a reflection coated mirror when he discovered something a bit more with the NGC 7331. He found a group of nearby galaxies! This faint gathering of five is better known as “Stephan’s Quintet” and its members are no further apart than our own Milky Way galaxy.
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Visually in a large scope, these members are all rather faint, but their proximity is what makes them such a curiosity. The Quintet is made up of five galaxies numbered NGC 7317, 7318, 7318A, 7318B, 7319 and the largest is 7320 (Right Ascension: 22 : 36.1 - Declination: +33 : 57). Even with a 12.5″ telescope, this author has never seen them as much more than tiny, barely there objects that look like ghosts of rice grains on a dinner plate. So why bother?
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What our backyard equipment can never reveal is what else exists within this area – more than 100 star clusters and several dwarf galaxies. Some 100 million years ago, the galaxies collided and left long streamers of their materials which created star forming regions of their own, and this tidal pull keeps them connected. The stars within the galaxies themselves are nearly a billion years old, but between them lay much younger ones. Although we cannot see them, you can make out the soft sheen of the galactic nucleii of our interacting group.
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Enjoy their faint mystery!
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<b>Sunday, September 16</b> – It’s New Moon! For those of you who have waited on the weekend to enjoy dark skies, then let’s add another awesome galaxy to the collection. Tonight set your sights towards Alpha Pegasi and drop due south less than 5 degrees to pick up NGC 7479 (Right Ascension: 23 : 04.9 - Declination: +12 : 19).
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Discovered by William Herschel in 1784. this tantalizing 11 magnitude barred spiral galaxy has had a supernova in its nucleus as recently as 1990. While the 16th magnitude event is no longer visible, smaller telescopes will easily pick out bright core and elongation of the central bar. Larger aperture will find this one a real treat as the spiral arms curl both over and under the central structure, resembling a ballet dancer “en pointe”. Congratulations! You’ve just observed Caldwell 44.
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Until next week? Wishing you clear skies!
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<i>Written by Tammy Plotner. NGC 7009 Image Credit: NOAO/AURA/NSF</i>
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-56115814752161780702012-09-06T12:29:00.001-07:002012-09-06T12:50:18.407-07:00Eye Candy: ALMA Studies A Sweet Star!<div class="separator" style="clear: both; text-align: center;">
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Are you ready to take one sweet trip to the eye-candy shop? That's just what the Atacama Large Millimeter/submillimeter Array (ALMA) did when a team of astronomers discovered simple sugar molecules in the gas surrounding a young star. Similar to our Sun, the star cataloged as IRAS 16293-2422 and its sweet envelope herald the fact that the building blocks of life can be present when a solar system forms. <a name='more'></a>
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The detected molecules are very similar to what we use on the table. This simple form of sugar known as glycolaldehyde could be used in baking... Baking possible life into a forming planetary system, that is. While glycolaldehyde has been detected twice in space so far, this is the first time it has been documented around a binary star system. The sugar molecules aren't close enough to be browned by the suns themselves, but located away from the stars at roughly a Uranus distance. This means the correct chemical compounds needed to spark life likely exists at the time of planetary formation. However, sugar isn't the only thing ALMA discovered... signatures of complex organic molecules, including ethylene glycol, methyl formate and ethanol were also present.
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“In the disc of gas and dust surrounding this newly formed star, we found glycolaldehyde, which is a simple form of sugar, not much different to the sugar we put in coffee,” explains Jes Jørgensen (Niels Bohr Institute, Denmark), the lead author of the paper. “This molecule is one of the ingredients in the formation of RNA, which — like DNA, to which it is related — is one of the building blocks of life.”
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According to the news release, the high sensitivity of ALMA — even at the technically challenging shortest wavelengths at which it operates — was critical for these observations, which were made with a partial array of antennas during the observatory’s Science Verification phase. Later this year, ALMA will go fully on-line by adding another 66 satellite dishes to improve her hearing. Even operating at a minimal capacity shows the huge potential of radio telescopes like Atacama.
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“What it is really exciting about our findings is that the ALMA observations reveal that the sugar molecules are falling in towards one of the stars of the system,” says team member Cécile Favre (Aarhus University, Denmark). “The sugar molecules are not only in the right place to find their way onto a planet, but they are also going in the right direction.”
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What makes this discovery so exciting? Gas and dust clouds compress upon themselves to form new stars - a cold process. During this time, gas can solidify and deposit as ice upon the dust particles. These particles can then bond together to form complex molecules. However, once the star forms in this rotating mass, it heats the interior to roughly room temperture - an action which destroys the chemically complex molecules. The resulting return to gas then emits a specific form of radiation and radio waves which can be detected and studied by sophisticated radio telescopes like ALMA.
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Located at about 400 light-years away, this sweet binary star system is close enough to be an excellent target for studying the molecules and chemistry around young stars. Thanks to the capabilities of telescopes like ALMA, researchers have the chance to study intricate details located in the gas and dust envelopes which could be forming planetary systems.
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"A big question is: how complex can these molecules become before they are incorporated into new planets? This could tell us something about how life might arise elsewhere, and ALMA observations are going to be vital to unravel this mystery,” concludes Jes Jørge.
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One lump or two?
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<i>Original Story Source: <a href="http://www.eso.org/public/news/eso1234/" target="blank">ESO News Release</a>. Image Credit: ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO) & NASA/JPL-Caltech/WISE Team.</i>
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-54462617275254784442012-09-03T16:48:00.003-07:002012-09-03T16:48:53.658-07:00Weekly SkyWatcher's Forecast: September 3-9, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! With the change in seasons becoming quickly apparent, it's time to put some early hours dark skies to good use and enjoy some favorite nebulae. If you've enjoyed the Mars-mania, then you'll also enjoy the return of Mars in the pre-dawn hours. Speaking of early mornings, be sure to watch as the Moon and Jupiter head for a splendid conjunction this coming Saturday. When you're ready, grab your binoculars and set up your telescopes... It's time to dance! <a name='more'></a>
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<b>Monday, September 3</b> - Tonight it’s time for us to head directly between the two lower stars in the constellations of Lyra and grab the “Ring”.
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First discovered by French astronomer, Antoine Darquier in 1779, the “Ring” was cataloged later that year by Charles Messier as M57 (Right Ascension: 18 : 53.6 - Declination: +33 : 02). In binoculars the “Ring” will appear as slightly larger than a star, yet it cannot be focused to a sharp point. To a modest telescope at even low power, the M57 turns into a glowing donut against a wonderfully stellar backdrop. The average accepted distance to this unusual structure is believed to be around 1,400 light years and how you see the “Ring” on any given night is highly attributable to conditions. As aperture and power increase, so do details and it is not impossible to see braiding in the nebula structure with scopes as small as eight inches on a fine night, or to pick up the star caught on the edge in even smaller apertures.
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Like all planetary nebula, seeing the central star is considered the ultimate of viewing. The central itself is a peculiar bluish dwarf which gives off a continuous spectrum and might very well be a variable. At times, this shy, near 15th magnitude star can be seen with ease with a 12.5″ telescope, yet be elusive to 31″ in aperture weeks later. No matter what details you may see, reach for the “Ring” tonight. You’ll be glad you did.
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<b>Tuesday, September 4</b> - Of course, studying some of the summer’s finest means that we’d be very remiss if we didn’t look at another cosmic curiosity – “The Blinking Planetary”.
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Located a couple of degrees east of visible star Theta Cygnii, and in the same lower power field as 16 Cygnii, the NGC 6826 (Right Ascension: 19 : 44.8 - Declination: +50 : 31) is often referred to as the “Blinking Planetary” nebula. Viewable in even small telescopes at mid to high power, you’ll learn very quickly how it came about its name. When you look directly at it, you can only see the central 9th magnitude star. Now, look away. Focus your attention on visual double 16 Cygnii. See that? When you avert, the nebula itself is visible. This is actually a trick of the eye. The central portion of our vision is more sensitive to detail and will only see the central star. At the edge of our vision, we are more likely to see dim light, and the planetary nebula appears. Located around 2,000 light years from our solar system, it doesn’t matter if the “Blinking Planetary” is a trick of the eye or not… Because it’s cool!
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<b>Wednesday, September 5</b> - If you’re up before dawn, maybe you’ve noticed the return of Mars? It’s been on the move and this universal date marks its official change in position from the constellation of Virgo into the constellation of Libra.
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Don’t put away your binoculars tonight just because you think this next study is beyond you… Just lift your sights three degrees higher than the “Omega” and tonight we’ll return again to fly with the “Eagle” - M16 (Right Ascension: 18 : 18.8 - Declination: -13 : 47)
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Small binoculars will have no trouble distinguishing the cluster of stars discovered by de Cheseaux in 1746, but larger binoculars and small telescopes from a dark sky site will also see a faint nebulosity to the region that was reported by Messier in 1764. This “faint light” will remind you highly of the reflection that is seen within the Pleiades, or “Rosette” nebula. While the most outstanding views of the “Eagle” nebula are in photographs, larger telescopes will have no problem picking out a vague cloud of nebula, encased stars and an unusual dark obscuration in the center which has always reminded this author as a “Klingon Bird of Prey”. While all of this is very grand, what’s really interesting is the little notch on the northeast edge of the nebula. This is easily seen under good conditions with scopes as small as 8″ and is undeniable in larger aperture. This tiny “notch” rocketed to worldwide fame when viewed through the eyes of the Hubble. It’s name? “The Pillars of Creation”.
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<b>Thursday, September 6</b> - Today celebrates the founding of the Astronomical and Astrophysical Society of America. Started in 1899, it is now known as the American Astronomical Society.
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Tonight let’s relax a little bit and have a look at a superb open cluster that stays superb no matter if you use small binoculars or a big telescope. Of whom do I speak so highly? M34 (Right Ascension: 2 : 42.0 - Declination: +42 : 47)…
Easily found on Perseus west border by scanning between Beta Perseii (Algol) and Gamma Andromeda (Almach), the M34 was discovered by Messier in 1764. Containing around 80 members, the central knot of stars is what truly makes it beautiful. At around 1400 light years away, this stellar collection is believed to be around 10 million years old. While binocular users are going to be very happy with this object, scopists are going to appreciate the fact that there is a double right in the heart of M34. This fixed pair is around magnitude 8 and separated by about 20″.
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<b>Friday, September 7</b> - Tonight we are going to take a journey once again toward an area which has intrigued this author since I first laid eyes on it with a telescope. Some think it difficult to find, but there is a very simple trick. Look for the primary stars of Sagitta just to the west of bright Albireo. Make note of the distance between the two brightest and look exactly that distance north of the “tip of the arrow” and you’ll find the M27 (Right Ascension: 19 : 59.6 - Declination: +22 : 43).
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Discovered in 1764 by Messier in a three and a half foot telescope, I discovered this 48,000 year old planetary nebula for the first time in a 4.5″ telescope. I was hooked immediately. Here before my eager eyes was a glowing green “apple core” which had a quality about it that I did not understand. It somehow moved… It pulsated. It appeared “living”.
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For many years I quested to understand the 850 light year distant M27, but no one could answer my questions. I researched and learned it was made up of doubly ionized oxygen. I had hoped that perhaps there was a spectral reason to what I viewed year after year – but still no answer. Like all amateurs, I became the victim of “aperture fever” and I continued to study the M27 with a 12.5″ telescope, never realizing the answer was right there – I just hadn’t powered up enough.
Several years later while studying at the Observatory, I was viewing through a friend’s identical 12.5″ telescope and as chance would have it, he was using about twice the magnification that I normally used on the “Dumbbell”. Imagine my total astonishment as I realized for the very first time that the faint central star had an even fainter companion that made it seem to wink! At smaller apertures or low power, this was not revealed. Still, the eye could “see” a movement within the nebula – the central, radiating star and its companion.
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Do not sell the “Dumbbell” short. It can be seen as a small, unresolved area in common binoculars, easily picked out with larger binoculars as an irregular planetary nebula, and turns astounding with even the smallest of telescopes. In the words of Burnham, “The observer who spends a few moments in quiet contemplation of this nebula will be made aware of direct contact with cosmic things; even the radiation reaching us from the celestial depths is of a type unknown on Earth…”
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<b>Saturday, September 8</b> - Heads up for early risers! This morning is a beautiful conjunction of Jupiter and the Moon. For viewers in the western regions of Southern America, this is an occultation event, so be sure to check for times in your area!
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Today in 1966, a legend was born as the television program Star Trek premiered. Created by Gene Roddenberry, its enduring legacy inspired several generations to an interest in space, astronomy, and technology. Its five-year mission still airs – along with numerous movie and series sequels. May Star Trek continue to “live long and prosper!”
Tonight a great opportunity to have another look at all the things we’ve studied this week. However, I would encourage those of you with larger binoculars and telescopes to head for a dark sky location, because tonight we are going on a quest… The quest for the holy “Veil”.
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By no means is the Veil Nebula Complex an easy one. The brightest portion, NGC 6992 (Right Ascension: 20 : 56.4 - Declination: +31 : 43), can be spotted in large binoculars and you can find it just slightly south of a central point between Epsilon and Zeta Cygnii. The NGC 6992 is much better in a 6-8″ scope however, and low power is essential to see the long ghostly filaments which span more than a degree of sky. About two and a half degrees west/southwest, and incorporating star 52 is another long narrow ribbon of what may be classified as a supernova remnant. When aperture reaches the 12″ range, so does the true breadth of this fascinating complex. It is possible to trace these long filaments across several fields of view. They sometimes dim and at other times widen, but like a surreal solar flare, you will not be able to tear your eyes away from this area. Another undesignated area lies between the two NGCs, and the whole 1,500 light year distant area spans over two and a half degrees. Sometimes known as the “Cygnus Loop”, it’s definitely one of the summer’s finest objects.
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<b>Sunday, September 9</b> - On this day in 1839, John Herschel froze time by making the very first glass plate photograph – and we’re glad he did. His photo was of his father William’s famous 40-foot telescope in Slough, England. The scope had not been used in decades and was disassembled shortly after the photograph was taken. Later in 1892, on this same day, Edward Emerson Barnard was busy at Lick Observatory discovering Jupiter’s innermost moon – Amalthea.
Do I always save the best for last? You bet. And tonight it’s my favorite galaxy structure – edge-on.
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The NGC 7814 (Right Ascension: 0 : 03.3 - Declination: +16 : 09) is easy enough to find. Just head towards Gamma Pegasi and look in your finderscope for a star that is around 3 degrees to the northwest. At low power you will see the galaxy to the southeast of this star as a scratch of light. Up the power in both aperture and magnification and enjoy! This galaxy has a deeply concentrated nucleus and a very prominent dissecting dark dustlane. By the way… It’s Caldwell 43.
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Until next week? Wishing you clear skies!
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<i>Written by: Tammy Plotner Four views of M57 - Credit: NOAO/AURA/NSF</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-89100668638902497202012-08-29T12:18:00.001-07:002012-08-29T12:18:54.270-07:00Let's Send Neil Back To The Moon<img src="http://www.universetoday.com/wp-content/uploads/2012/08/Pic-2.-Neil-Armstrong-Tribute-580x297.png" alt="" title="Pic 2. Neil Armstrong Tribute" width="580" height="297" class="aligncenter size-medium wp-image-97114" />
As a native-born and life-long resident of Ohio, I have lived in the shadow of Neil Armstrong all my life. I visit Wapokenta every few years for two simple reasons - I love the Armstrong Museum and I feel a need to pass that heritage on to children, grandchildren and visiting friends. Of course, I was crushed when I read of his death. I would have given anything to have had Armstrong's autograph on my original Apollo landing newspapers, or even just to have seen the man. He was a humble hero... and this is the quality that I loved most about him. However, Neil Armstrong and his quiet ways didn't just impact my life. He touched us all. <a name='more'></a>
"Early on Sunday morning here in Australia I got the news I never wanted to hear." says Dave Reneke of Australia. "I was in the middle of a radio interview on a local station when they cut in with the news that Neil Armstrong had passed away. “What?? What are you telling me…Neil’s dead!!” I cut the interview short because I simply couldn’t go on.
Neil Armstrong wasn’t just an American hero; he belonged to the entire world. Kids wanted to be like him. Men looked up to him and every woman wanted to be Mrs. Neil Armstrong. My world had just collapsed and I didn’t know what to do.
A humble man who, as a kid, only ever wanted to fly, Neil went on to pilot the famous X-15 rocket plane, fly dozens of dangerous missions during the Korean War and later travel in space with Dave Scott on the Gemini 8 mission in 1966. He was unknowingly paving the way for his ultimate destiny to be the first man to walk on the Moon a mere 3 years later.
There will never be another event like this. If anything epitomises the twentieth century it was the first Moon landing. Our first steps on another world. Those of us who witnessed it remember where they were at the time, just as we did when Elvis died and Kennedy was assassinated. Tragedy imprints, indelibly!
For 12 hours during and throughout that moon walk period there was virtually no crime around the world. One in six human beings were watching the moon landing on TV, even the crims, and listening on radios. For a moment in time we were united – we knew, we just knew we were witnessing one of the greatest events in history unfold right before our very eyes.
You only get one shot at this. Only one person can walk on the moon for the first time. It took guts – the ‘right stuff!’ Neil gave them a 50/50 chance of getting to the Moon and getting back. Nasa’s odds were about the same. They were both 38 years old with families and a whole lifetime in front of them, but they went.
I was lucky enough to be invited to spend the morning with Buzz Aldrin at his home in California in 2008, prior to writing a story about the upcoming 40th anniversary of Apollo 11. I remember asking Buzz what concerned them the most, what was the one thing they were concerned about and feared the most.
Both he and Neil had two days cooped up in a small capsule to think about that. He paused, looked up and surprised me by saying they were very aware they were being watched. “We knew that everything we did and everything we said was being recorded for future history,” Buzz said. “It was on our minds constantly.”
OK, it’s over. Neil Armstrong’s name will live on from this day forward. He’s gone beyond the term legend. In the annals of history he’ll be seen as a giant, the Wilbur Wright of our time. Hundreds of years from now kids in a future classroom will be learning about Neil Armstrong, as we studied ancient history in our day.
<img src="http://www.universetoday.com/wp-content/uploads/2012/08/Pic-1.-Neil-Armstrong-Banner-580x324.png" alt="" title="Pic 1. Neil Armstrong Banner" width="580" height="324" class="aligncenter size-medium wp-image-97115" />
But hang on, do we leave it all here? Is this where the story ends? Let’s do something about it, something quite radical but completely sensible. Let’s send Neil Armstrong back to the Moon! Not literally but posthumously. Let’s start a movement that will reverberate back to NASA, to the white house and engage a lobby group to have Neil Armstrong’s ashes interred on the Moon.
I’m proposing a monument to be built on the Sea Of Tranquillity, on the spot where Neil and Buzz walked and, if there’s no national burial planned, place his ashes there. An eternal symbol and testament to human accomplishment – as Neil put it, the place where men from planet Earth first set foot on the Moon, and came in peace for all mankind.
Let it be slated for the first Moon return mission, by any country or private consortium. A stone minimally inscribed with a simple message telling the story for future generations. The blood, sweat, tears and spirit of countless thousands who worked on the Moon missions would be indelibly imprinted on it. Even the words ‘Neil and Buzz were here’ would satisfy me.
We’ve got the ‘Monument to a Century of Flight’ located at the Aycock Brown Welcome Centre at milepost 1.5 in Kitty Hawk, NC, the Smithsonian cradles flight history and the ashes of people like Gene Rodenberry, James Doohan et al circle the earth in tributary gestures.
Neil’s remains would be in good company on the Moon sharing the eternal silence with the ashes of Eugene Shoemaker. If you just asked “who” Google the name, it’s a great story. Folks, this is not something we need to do, it’s something we should do!"
The author of this narrative would like to hear any feedback, especially if you’re in a position to help make this happen. Contact Dave Reneke, writer and publicist for Australasian Science magazine via his webpage www.davidreneke.com or email davereneke@gmail.com
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-52703331390611258522012-08-27T08:50:00.000-07:002012-08-29T12:17:53.107-07:00Blue Moon This Week<div class="separator" style="clear: both; text-align: center;">
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When you hear someone say “Once in a Blue Moon” you know what they mean. They’re usually talking about something rare, silly, and even absurd. After all, when was the last time you saw the Moon turn blue? Well, rare or not, we’re having one this week, and according to astronomer David Reneke writer and publicist for Australasian Science magazine, a Blue Moon is slated for the last day of this month, Friday, August 31. <a name='more'></a>
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It's not at all clear where the term ‘Blue Moon’ comes from. According to modern folklore it dates back at least 400 years. A Blue Moon is the second Full Moon in a calendar month. “Usually months have only one Full Moon, but occasionally a second one sneaks in, David said. “Ancient cultures around the world considered the second Full Moon to be spiritually significant.”
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Full Moons are separated by 29 days, while most months are 30 or 31 days long, so it is possible to fit two Full Moons in a single month. This happens every two and a half years, on average. By the way, February is the only month that can never have a Blue Moon by this definition. We had one Full Moon on August 2 this year and the second will be Friday night.
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Does the Blue Moon actually turn blue? No. Physically colored Blue Moons are rare, and that's where the phrase comes from, "Once in a Blue Moon". There are occasions though when pollution in the Earth's atmosphere can make the Moon appear to look blue in color. The extra dust scatters blue light. For example, the Moon appeared bluish green across the entire Earth for about 2 years after the eruption of Krakatoa in 1883.
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There were also reports of a blue-green coloured Moon caused by Mt. St. Helens in 1980 and Mount Pinatubo in 1991. “So in a sneaky sort of way, it could be true,” Dave said with a grin. Look up at the night sky on August 31 and see for yourself. Everywhere in the world the full Moon rises in the east just as the Sun is setting in the west.
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“Blue Moons don’t have any real significance scientifically but they’re fun to look at,” David said. “Anytime you can get people out to look at the real sky to me is a great plus, enjoy it while you can this Friday night and while you’re looking moonward, think of Neil Armstrong, OK?”
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<i>Story Contributed by <a href="http://www.davidreneke.com" target="blank">Dave Reneke</a>. Image Credit: John Chumack</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-9878477757300967942012-08-26T15:59:00.000-07:002012-08-27T08:51:45.162-07:00Weekly SkyWatcher's Forecast: August 27-September 2, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! If you only get your telescope or binoculars out once in a Blue Moon, then get them out this week when a Blue Moon actually happens! However, if you can't wait, then let's explore some great lunar features, bright star clusters and great double stars. When you're ready to learn some history, mystery and more, then just step on inside... <a name='more'></a>
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<b>Monday, August 27</b> – Tonight the waxing Moon’s most notable features will be the vast area of craters dominating the south-central portion near and along the terminator. Now emerging is Ptolemaeus – just north-northeast of Albategnius. This large round crater is a mountain walled plain filled with lava flow. With the exception of interior crater Ptolemaeus A, binoculars will see it as very smooth. Telescopes, however, can reveal faint mottling in the surface of the crater’s interior, along with a single elongated craterlet to the northeast. Despite its apparent uniformity, close inspection has revealed as many as 195 interior craterlets within Ptolemaeus! Look for a variety of interior ridges and shallow depressions.
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With the Moon low to the southwest, we have a chance to go northeast to Cepheus for a new study – NGC 7160 (Right Ascension: 21 : 53.7 (hours : minutes) Declination: +62 : 36). At magnitude 6.1, this small open cluster is easily identified in scopes and may be seen as a faint starfield in binoculars. You’ll find it about a finger-width north of Nu Cephei.
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<b>Tuesday, August 28</b> – In 1789 on this day, Sir William Herschel discovered Saturn’s moon Enceladus. <br><br>
On the lunar surface tonight, we’ll start by following the southward descent of large crater rings Ptolemaeus, Alphonsus, and Arzachel to a smaller, bright one southwest named Thebit. We’re going to have a look at Hell…
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Just west of Thebit and its prominent A crater to the northwest, you see the Straight Wall – Rupes Recta – appearing as a thin, white line. Continue south until you see large, eroded crater Deslandres. On its western shore, is a bright ring that marks the boundary of Hell. While this might seem like an unusual name for a crater, it was named for an astronomer – and clergyman!
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Once you’ve been to Hell, let’s go to the heavens for NGC 7235 (Right Ascension: 22 : 12.6 - Declination: +57 : 17). Locate the star crowded area of Epsilon Cephei which will also include this 7.7 magnitude open cluster in the same low power field. Give it a try. Look for a small, rectangular assortment of 10th magnitude and fainter stars, including a beautiful ruby red, west-northwest of Epsilon.
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<b>Wednesday, August 29</b> – Due south of mighty Copernicus on the eastern edge of Mare Cognitum, you will see a ruined pair of flattened craters. They are Bonpland and Parry – with Frau Mauro just above them. The smallest and brightest of these ancient twins is the eastern Parry. Have a look at its south wall where a huge section is entirely lost. It was near this location that Ranger 7 ended its successful flight in 1964. Just south of Parry is another example of a well-worn Class V crater. See if you can distinguish the ruins of Guericke. Not much is left save for a slight U-shape to its battered walls. These are some of the oldest visible features on the Moon!
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If you’d like to head for something very young, have a look at 6.8 magnitude open cluster NGC 6811 (Right Ascension: 19 : 37.3 - Declination: +46 : 23) in Cygnus. This mid-sized, unusually dense open cluster is found less than finger-width north-northwest of Delta – the westernmost star of the Northern Cross. Like most open clusters, the age of NGC 6811 is measured in millions, rather than billions, of years. Visible in binoculars on most nights, telescopes should show a half dozen or so broadly-spaced resolvable stars overlaying a fainter field. Be sure to return again on a moonless night, and have another look a disparate double Delta!
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<b>Thursday, August 30</b> – Today celebrates the Yohkoh Mission, launched in 1991. It was a joint effort of both Japan and the United States to monitor solar flares and the corona. While its initial mission was quite successful, on December 14, 2001 the signal was lost during a total eclipse. Unable to reposition the satellite back towards the Sun, the batteries discharged and Yohkoh became inoperable.
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While the graceful Gassendi will try to steal the lunar show tonight, let’s have a go at Foucault instead. To find it, head north to Sinus Iridum and locate Bianchini in the Juras Mountains. Just northeast, and near the shore of south-eastern Mare Frigoris, look for a bright little ring.
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Physicist Jean Foucault played an instrumental role in the creation of today’s parabolic mirrors. His “Foucault knife edge test” made it possible for opticians to test mirror curves for optical excellence during the final phases of shaping before metallization. Thanks to Foucault’s insight, we can turn our telescopes on such difficult double stars as Beta Delphini and resolve its 0.6 arc-second distant 5.0 magnitude companion. A challenge for smaller scopes is MU Cygni. This 4.5 and 6.0 magnitude pair should be resolvable in any scope that passed Foucault’s test!
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Tonight let’s view a double star, Eta Lyra. Just on the edge of unaided visibility, you will find it around three finger-widths due east of Vega. This wide, disparate pair of 4.5 and 8.0 magnitude stars should be resolvable in just about any scope, but is beyond the reach of binoculars.
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<b>Friday, August 31</b> – Tonight we will begin entering the stream of the Andromedid meteor shower, which peaks off and on for the next couple of months. For those of you in the northern hemisphere, look for the lazy “W” of Cassiopeia to the northeast. This is the radiant – or relative point of origin – for this meteor stream. At times, this shower has been known to be spectacular, but let’s stick with an accepted fall rate of around 20 per hour. These are the offspring of Beila’s Comet, one that split apart leaving radically different streams – much like 73/P Schwassman-Wachmann did last year. These meteors have a reputation for red fireballs with spectacular trains, so watch for them in the weeks ahead.
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It’s Blue Moon! That doesn’t mean the Moon is going to be colored any differently – it just means it’s the second full Moon within a month.
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Think having all this Moon around is the pits? Then let’s venture to Zeta Sagittarii and have a look at Ascella – “The Armpit of the Centaur.” While you’ll find Zeta easily as the southern star in the handle of the teapot formation, what you won’t find is an easy double. With almost identical magnitudes, Ascella is one of the most difficult of all binaries. Discovered by W. C. Winlock in 1867, the components of this pair orbit each other very quickly – in just a little more than 21 years. While they are about 140 light-years away, this gravitationally bound pair waltz no further apart than our own Sun and Uranus!
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Too difficult? Then have a look at Nu Sagittarii – Ain al Rami, or the “Eye of the Archer.” It’s one of the earliest known double stars and was recorded by Ptolemy. While Nu 1 and Nu 2 are actually not physically related to one another, they are an easy split in binoculars. Eastern Nu 2 is a K type spectral giant that is around 270 light-years from our solar system. But take a very close look at the western Nu 1 – while it appears almost as bright, this one is 1850 light-years away! As a bonus, power up in the telescope, because this is one very tight triple star system!
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<b>Saturday, September 1</b> – On this day 1859, solar physicist Richard Carrington (who originally assigned sunspot rotation numbers) observed the first solar flare ever recorded. Naturally enough, an intense aurora followed the next day. 120 years later in 1979, Pioneer 11 made history as it flew by Saturn.
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While the Moon essentially appears to be full throughout the night, take the time to compare the western and eastern limbs. To the west, you will see the smooth arc no longer displays high contrast features. To the east you should see a broken edge now in sunset. Watch in the days ahead as many of your favorite craters begin to reveal themselves in a “different light.”
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Tonight let’s visit Alya. One of the fainter stars to receive a proper name, Theta Serpens Caput is located around a hand span due east of Beta Ophiuchi. Thankfully, resolving this wide, matched magnitude pair is easier than finding it. If you have high power, self-stabilizing binoculars, this one could be real fun!
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<b>Sunday, September 2</b> - It won’t be long until the Moon lights the skies, so let’s have a look at disparate double Kappa Pegasi. It’s the westernmost star of northern Pegasus and is around a hand span due south of Sadr – the central star of the Northern Cross. At magnitude 4.3, look for a faint companion leading the orange-yellow primary across the sky. This one could be tough for small scopes – so make a challenge of it!
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Now let’s have a look at Beta and Gamma Lyrae – the lower two stars in the “Harp.” Beta is actually a quick change variable dropping to less than half the brightness of Gamma every 12 days, but for a few days the two stars appear to be of near equal brightness. Beta is a very unusual eclipsing spectroscopic binary. Its unseen companion may be a “collapsar.”
Before you call it a night, head a finger-width north of Omicron Andromedae for 15 Lacertae. Just on the edge of unaided visibility, this carbon star is also a disparate double. The 5.2 magnitude variable primary will appear more red at its faintest, but its 11.0 magnitude companion is the faintest of all!
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But don’t put the telescope away just yet. If you can locate the Moon, you can locate Uranus! Just take a look about 3 degrees away to lunar south to catch the slightly greenish orb of the outer planet.
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Until next week, ask for the Moon... But keep on reaching for the stars!
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<i>Written by Tammy Plotner. Ptolemaeus Crater Image Credit: Damian Peach</i>
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-61563716820347189882012-08-24T09:24:00.000-07:002012-08-24T09:24:04.353-07:00Star Consumes Its Planet<div class="separator" style="clear: both; text-align: center;">
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So far we've discovered a huge amount of planets orbiting a variety of stars, but this is the first time astronomers have uncovered evidence of a star devouring one of its offspring. When a planet comes up "missing", it's time to take a closer look at its parent star - in this case, a red giant older than the Sun and about eleven times bigger. <a name='more'></a>
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“A similar fate may await the inner planets in our solar system, when the Sun becomes a red giant and expands all the way out to Earth’s orbit some five-billion years from now,” said Alexander Wolszczan, Evan Pugh Professor of Astronomy and Astrophysics at Penn State University, who is one of the members of the research team. Wolszczan also is the discoverer of the first planet ever found outside our solar system.
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However, that's not all that's been discovered in this odd solar system. The same red giant star, named BD+48 740, appears to have a massive planet contained in a highly elliptical orbit. Wolszczan and the team’s other members, Monika Adamow, Grzegorz Nowak, and Andrzej Niedzielski of Nicolaus Copernicus University in Torun, Poland; and Eva Villaver of the Universidad Autonoma de Madrid in Spain, were hard at work utilizing the Hobby-Eberly Telescope in search of its solar system when they uncovered evidence of planetary destruction. Just what was the clue? Try an unusual chemical composition of the host star and the strange elliptical orbit of a surviving planet.
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“Our detailed spectroscopic analysis reveals that this red-giant star, BD+48 740, contains an abnormally high amount of lithium, a rare element created primarily during the Big Bang 14 billion years ago,” Adamow said. Lithium is easily destroyed in stars, which is why its abnormally high abundance in this older star is so unusual. “Theorists have identified only a few, very specific circumstances, other than the Big Bang, under which lithium can be created in stars,” Wolszczan added. “In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet that spiraled into the star and heated it up while the star was digesting it.”
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As for the remaining planet, it's pretty incredible. This newly discovered member is 1.6 times as massive a Jupiter. “We discovered that this planet revolves around the star in an orbit that is only slightly wider than that of Mars at its narrowest point, but is much more extended at its farthest point,” Niedzielski said. “Such orbits are uncommon in planetary systems around evolved stars and, in fact, the BD+48 740 planet’s orbit is the most elliptical one detected so far.” Because gravitational interactions between planets are responsible for such peculiar orbits, the astronomers suspect that the dive of the missing planet toward the star before it became a giant could have given the surviving massive planet a burst of energy, throwing it into an eccentric orbit like a boomerang.
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“Catching a planet in the act of being devoured by a star is an almost improbable feat to accomplish because of the comparative swiftness of the process, but the occurrence of such a collision can be deduced from the way it affects the stellar chemistry,” Villaver explained. “The highly elongated orbit of the massive planet we discovered around this lithium-polluted red-giant star is exactly the kind of evidence that would point to the star’s recent destruction of its now-missing planet.”
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Bon apetit!
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<i>Original Story Source: <a href="http://science.psu.edu/news-and-events/2012-news/Wolszczan8-2012" target="blank">Penn State News Release</a>. Photo Credits: NASA</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-67107471180462493582012-08-20T12:00:00.000-07:002012-08-20T12:02:33.898-07:00Weekly SkyWatcher's Forecast: August 20-26, 2012
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Greetings, fellow SkyWatchers! It's going to be a great week to catch up on your lunar studies, but be sure to mark your calendar for Tuesday's splendid conjunction! There will be bright stars and clusters to study, so enjoy these temperate nights while they last! Whenever you're ready to learn more about the history, mystery and majesty of what's out there, meet me in the back yard... <a name='more'></a>
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<b>Monday, August 20</b> – Tonight the Moon sets by skydark, but if you’re looking for a lunar challenge, return to crater Petavius about one-third the way up from the southern cusp just after sunset. This ancient crater is a wonderland of detail when lying on the terminator. Look for its rugged walls interrupted by crater Wrottesley to the northwest and elongated Palitzsch southeast. If conditions are stable, power up to look for a massive, multi-peaked central mountain region, along with a deep scar – Rima Petavius – cutting diagonally across the wavelike floor.
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When the Moon has set, look for the southern Crown – Corona Australis. Its hidden jewel is 7.3 magnitude, 28,000 light-year distant globular cluster NGC 6723 (Right Ascension: 18 : 59.6 - Declination: -36 : 38). Discovered on June 3, 1826 by James Dunlop of New South Wales, Australia, NGC 6723 can be best found by heading less than 7 degrees due south of Zeta Sagittarii. This mid-sized cluster gives a surprising view, but if you’re more north, best catch it at its highest.
Now, relax! Tonight is the peak of the Kappa Cygnid meteor shower. Although the Moon will interfere early in the evening, wait until it has set and watch the area near Deneb. Discovered in the late 1800′s, the Kappa Cygnids are often overlooked because the grander, more prolific Perseids tend to get more attention. Although the stream has been verified, peak dates and fall rates vary from year to year. The average fall rate is usually no more than 5 per hour, but it is not uncommon to see 12 or more per hour with many fireballs. The stream’s duration is around 15 days. Clear skies!
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<b>Tuesday, August 21</b> – Deep Blue Celestial Scenery Alert! Don’t goof around tonight. Find yourself an open western horizon and be outside at sky dark for the awe inspiring combination of the Moon, Spica, Mars and Saturn. The powerful blue/white star will be located just northeast of the lunar edge while Mars resides to the east/southeast and Saturn reigns above them all. This will be a very photographic opportunity, so be sure to take advantage of this splendid conjunction. Tell your family and friends!
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Although we have traveled this road before, let’s go further south than last night’s lunar study and have another look at Furnerius. Shallower and less impressive than Petavius, Furnerius will fade to obscurity as the Moon waxes. This flooded old crater has no central peak, but a much younger crater has punched a hole in its lava-filled floor. Look for the long “crack” extending from Furnerius’ north shore to crater rim. Perhaps it was caused by the impact? Sharp-eyed observers with good conditions and high power will also spot a multitude of small craters within and along Furnerius’ walls. For binocular viewers, try spotting crater Stevinus to the north and Fraunhofer to the south.
Now let’s go have a look at a star buried in one of the spiral arms of our own galaxy – W Sagittarii…
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Located less than a fingerwidth north of Gamma, the tip of the “teapot spout,” W is a Cepheid variable that’s worth keeping an eye on. While its brightness only varies by less than a magnitude, it does so in less than 8 days! Normally holding close to a magnitude 4, nearby field stars will help you correctly assess when minimum and maximum occur. While it’s difficult for a beginner to see such changes, watch it over a period of time. At maximum, it will be only slightly fainter than Gamma to the south. At minimum, it will be only slightly brighter than the stars to its northeast and southwest.
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While you watch W go through its changes – think on this: not only is W a Cepheid variable (a standard for distance measurements), but it is also one that periodically changes its shape. Not enough? Then think twice… Because W is also a Cepheid binary. Still not enough? Then you might like to know that recent research points toward W having a third companion as well!
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<b>Wednesday, August 22</b> – On the lunar surface tonight, head to the eastern shore of Mare Nectaris to catch an easily noticed broken black line. This is the western flank of the Pyrenees Mountains which stretch close to 350 kilometers north to south. The black line you see is a good example of a lunar scarp, a feature more like a cliff than a true mountain range. This scarp ends to the north in crater Guttenberg. Just south of Guttenberg, you will find high contrast Santbech.
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Although it will be tough to locate with the unaided eye thanks to the Moon, let’s take a closer look at one of the most unsung stars in this region of sky – Eta Sagittarii. This M-class giant star will show a wonderful color contrast to binoculars or scopes, being slightly more orange than the surrounding field. Located 149 light-years away, this irregular variable star is a source of infrared radiation and is a little larger than our own Sun – yet 585 times brighter. At around 3 billion years old, Eta has either expended its helium core or just begun to use it to fuse carbon and oxygen – creating an unstable star capable of changing its luminosity by about 4%. But have a closer look… For Eta is also a binary system with an 8th magnitude companion!
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<b>Thursday, August 23</b> – Do you remember a few days ago in history when Lunar Orbiter 1 was launched? Well, on this day in history it made headlines as it sent back the very first photo of Earth seen from space!
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On the lunar surface tonight, we’ll return to identify Metius, Fabricus and Janssen to the south. Southwest of this trio you will see a sharply defined small crater known as Vlacq. Power up to resolve its small central mountain peak. Angling off to the west and extending westward is multiple crater Hommel. Look especially for Hommel A and Hommel C which fit nicely and precisely within the borders of the older crater. Note how many individual craters make up its borders. Just north of Hommel is Pitiscus and to its south is Nearch.
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Now let’s have a look at the brightest star in the “Archer” – Epsilon Sagittarii. Known as Kaus Australis, or the “Southern Bow,” Epsilon holds a respectable magnitude 1.8 and is located around 120 light-years from Earth. This sparkling blue/white star is 250 times brighter than our own Sun. While a major challenge would be to spot Epsilon’s 14th magnitude companion star located about 32″ away, even the smallest of telescopes and most binoculars can try for the 7th magnitude visual companion widely spaced to the north-northwest.
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<b>Friday, August 24</b> – Today in 1966 from an Earth-orbiting platform, the Luna 11 mission was launched on a three day trip. After successfully achieving orbit, the mission went on to study many things, including lunar composition and nearby meteoroid streams.
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Tonight’s prominent lunar features are also Astronomical League challenges. Look southwest of previous study Theophilus for the huge form of Maurolycus. Its cratered floor may be either partially lit or fully disclosed depending on your observing time. Note especially Maurolycus’ multiple central mountains. North of Maurolycus you will see the well-eroded remains of Gemma Frisius. Its broken walls will show well under current illumination. Finally look carefully for crater Goodacre which has destroyed Gemma Frisius’ northern wall.
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The Moon is now becoming the “highlight” of the night sky. Try using “higher power” to diminish some of its glare. While southwestern Sagittarius is also high, why not observe some of its other globular clusters?
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Center the scope on Epsilon and sweep less than 3 degrees north-northeast to find small 7.7 magnitude globular M69 (Right Ascension: 18 : 31.4 - Declination: -32 : 21). M69 gives an appearance similar to that of other compact clusters – such as M28 and M80. Small and moderately bright, it appears coarsely textured through smaller instruments and requires larger scopes to bring out its brightest 14th magnitude members. This cluster sits near a blue 7th magnitude star which complicates seeing M69 through binoculars and finderscopes.
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Now head a little more than a degree southeast, then north of a pair of 6th magnitude stars to locate NGC 6652 (Right Ascension: 18 : 35.8 - Declination: -32 : 59) – a very small 9th magnitude globular. Go less than 2 degrees northeast to find brighter (8.1 magnitude), larger M70 (Right Ascension: 18 : 43.2 - Declination: -32 : 18). Notice how more of M70′s light is concentrated in its core than M69. Continuing a little more than 3 degrees in the direction of Zeta we encounter M54 (Right Ascension: 18 : 55.1 - Declination: -30 : 29). Through a modest scope, this 7.7 magnitude globular is small, very blue, and intensely concentrated at the core. Larger amateur instruments will only bring out a few 15th magnitude members out of this globular’s faintly glowing form.
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Charles Messier discovered M69 and M70 on August 31, 1780 from Paris while trying to confirm a discovery made by Lacaille using a half-inch spyglass in South Africa. These two globulars lie within 2,000 light-years of each other and less than 30,000 light-years from Earth. Due to unusual richness in metal content – for astronomers, “metals” are any elements other than hydrogen and helium – M69 may be a relatively young cluster. At some 90,000 light-years, M54 is the most distant Messier globular cluster – and may not be a globular at all – but the core of a dwarf galaxy beyond the bounds of the Milky Way! In fact M54 is intrinsically larger (300 light-years in diameter) and brighter (magnitude 10.1) than any other globular within the Milky Way itself.
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<b>Saturday, August 25</b> – Tonight the waxing Moon’s most notable features will be the vast area of craters dominating the south-central portion near and along the terminator. Now emerging is Ptolemaeus – just north-northeast of Albategnius. This large round crater is a mountain walled plain filled with lava flow. With the exception of interior crater Ptolemaeus A, binoculars will see it as very smooth. Telescopes however can reveal faint mottling in the surface of the crater’s interior, along with a single elongated craterlet to the northeast. Despite its apparent uniformity, close inspection has revealed as many as 195 interior craterlets within Ptolemaeus! Look for a variety of interior ridges and shallow depressions.
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With the moonlight causing studies to be mildly hampered, our main feature for tonight will definitely improve once the Moon sets – so while we’re waiting, let’s drop by open cluster M29 (Right Ascension: 20 : 23.9 - Declination: +38 : 32) less than 2 degrees south-southeast of Gamma Cygni. At lower power, or through small scopes, its handful of brightest members makes this 6.6 magnitude open cluster look more like an asterism than a real group. Lacking any sense of a core, higher power and larger scopes will bring out another dozen or so stars. Those with binoculars will enjoy seeing a few of M29′s brightest stars against a vague nebulosity.
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Now let’s see what the “I” can “C”… Less than 2 degrees southwest of M29 (just south of 5th magnitude P Cygni) lies another open cluster of similar brightness and size to M29 – IC 4996 (Right Ascension: 20 - : 16.5 - Declination: +37 : 38). How do these two compare? The less conspicuous IC 4996 lies in a richer Milky Way field and consists of fewer and more compact bright stars. Smaller scopes see this one as a patch of nebulosity.
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Now for M55 (Right Ascension: 19 : 40.0 - Declination: -30 : 58). Found in the far reaches of eastern Sagittarius, and west-southwest of Zeta, M55 is one of the coarsest globulars known. At magnitude 7.0, M55 can be seen as a large pale ghost of luminosity in binoculars or finderscopes. This is one very open globular cluster! A multitude of fine, easily resolved stars spread oblately over the mid-power field. Long exposure photos show this to be a true globular glowing with the combined light of almost 100,000 suns.
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Tonight is also the peak of the Northern Iota Aquarid meteor shower. While the Moon will totally interfere most of the evening, you still might catch a bright streak!
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<b>Sunday, August 26</b> – The most outstanding feature tonight on the Moon will be a southern crater near the terminator - Maurolycus. Depending on your viewing time, the terminator may be running through it. These shadows will multiply its contrast many times over and display its vivid formations. As true lunar challenge, Maurolycus will definitely catch your eye with its black interior and western crest stretched over the terminator's darkness. Too many southern craters to be sure? Don't worry. Maurolycus dominates them all tonight. Look for its double southern wall and multiple crater strikes along its edges. Maurolycus is found about two Crisium lengths southwest of Theophilus and in tonight's light will appear especially fine. But look just north of Maurolycus to pick out the battered remains of Class III crater Gemma Frisius, another lunar challenge. Spanning 56 miles and descending 17,100 feet below the Moon's surface, you'll find its walls broken, yet enough of its northern boundary remains to clearly reveal the impact that created Goodacre. Look for the shadows which blend Goodacre and Gemma Frisius together.
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On this date in 1981, Voyager 2 made a fly-by of Saturn. Eight years later in 1989, Voyager 2 flew by Neptune on this date. Why don’t we make a “date” tonight to have a look at this distant blue world? You’ll find it on the ecliptic plane. While large binoculars can pick up Neptune’s very tiny blue orb, you’ll need a telescope tonight to spot it through the lunar glare.
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Until next week? Wishing you clear skies!
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<i>Written by Tammy Plotner. Photo Credit: Petavius - Damian Peach</i>
Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-74073364482157827232012-08-12T16:41:00.000-07:002012-08-12T16:41:33.718-07:00Weekly SkyWatcher's Forecast: August 13-19, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! Even if you missed the peak of the Perseid meteor shower, there will still be plenty of "strays" to sparkle this week's dark nights. For astronomy without a telescope, be sure to check out all the planetary alignments - and tell your friends! When you're ready to learn more about what to view and when this week, then meet me in the back yard... <a name='more'></a>
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<b>Monday, August 13</b> – Celestial scenery alert! If you’re out before dawn this morning, look for the very close pairing of Venus and the slender crescent Moon. For viewers in the north-eastern Asia area, this is an occultation event, so be sure to check resources for times and locations in your area! How about some more eye candy? Then check out the splendid alignment of Saturn, Mars and Spica just after sky dark. Look for the blue/white star to the west, accompanied by red Mars to the east and yellow Saturn even higher to the east. The trio will be roughly separated by the same distance from each other and the colors will be a welcome sight. Be sure to alert your family and friends to all the celestial action that doesn’t require a telescope today!
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Tonight, begin with just your eyes as you gaze about four fingerwidths above the top of the Sagittarius “teapot dome” for an open window on the stars and mighty M24 (Right Ascension: 18 : 18.4 - Declination: -18 : 25)…
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This huge, hazy patch of stars is in reality an area of space known as “Baade’s Window” – an area free of obscuring gas and dust. Cataloged by Messier in 1764 as object 24, even small binoculars will reveal the incredible vista of the “Sagittarius Star Cloud.” Although it’s actually not a cluster, but rather a clean view of an area of our own galaxy’s spiral arm, that will not lessen the impact when viewed through a telescope. Spanning a degree and a half of sky, it is one of the few areas in which even a novice can easily perceive areas of dark dust.
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For larger telescopes, look for the dim, open cluster NGC 6603 (Right Ascension: 18 : 18.4 - Declination: -18 : 25) in the northeastern position of the Window. There are two very notable dark nebulae, B92 and B93, located in the northern segment as well. Near teardrop shaped B92 and its single central star, you should spot open cluster Collinder 469 and also Markarian 38 south of B93. You’ll find B86 near Gamma Sagittarii . At the southern edge of the star cloud, look for emission nebula IC 1283-1284, along with the reflection nebulae NGC 6589 (Right Ascension: 18 : 16.9 - Declination: -19 : 46) and NGC 6590 (Right Ascension: 18 : 17.0 - Declination: -19 : 53) and open cluster NGC 6595 (Right Ascension: 18 : 17.0 - Declination: -19 : 53). Still up for more? Then head west to see if you can find 12th-magnitude planetary nebula NGC 6567 (Right Ascension: 18 : 13.7 - Declination: -19 : 05).
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Even if you don’t accept these challenges, you can still enjoy looking at a 560 light-year swatch of stars from one of the Milky Way’s loving arms! (If you’re out late, look for Mira… It was discovered by Fabricius on this date in 1596.)
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<b>Tuesday, August 14</b> – Celestial scenery alert! Be out just after sunset to catch a splendid stellar and planetary conjunction. To the west you’ll see bright Spica. Just above it, Mars. And just above that? Saturn! The trio are all separated by just a few degrees, so be sure to stop and enjoy!
Your first challenge for tonight will be to venture about three fingerwidths northeast of Lambda Sagittarii to visit a well-known but little visited galactic cluster – M25 (Right Ascension: 18 : 31.6 - Declination: -19 : 15).
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First discovered by Cheseaux and then cataloged by Messier, it was observed and recorded by William Herschel, Johann Elert Bode, Admiral Smythe and T. W. Webb…but never added to the NGC catalog of John Herschel! Thanks to J.L.E. Dreyer, it did make the second Index Catalog as IC 4725.
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Seen with even the slightest optical aid, this 5th magnitude cluster contains two G-type giants as well as a Delta Cephei-type variable with the designation of U, which changes about one magnitude in a period of less than a week. It’s very old for an open cluster, perhaps near 90 million years, and the light you see tonight left the cluster over 2000 years ago. While binoculars will see around a double handful of bright stars overlaying fainter members, telescopes will reveal more and more as aperture increases. At one time it was believed to have only about 30 members, but this was later revised to 86. But recent studies by Archinal and Hynes indicate it may have as many as 601 member stars!
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<b>Wednesday, August 15</b> – Celestial scenery alert! Get up before dawn to spot Mercury low on the eastern horizon, a very tiny crescent Moon to its west/southwest and brilliant Venus ruling above it all! To add to the mix, you’ll see the pairing of the Gemini Twins – Castor and Pollux – just about a handspan above Mercury and luminous Procyon about the same distance due south. If you missed your opportunity to view Spica, Mars and Saturn on Monday, don’t worry. The colorful trio is still around tonight just after sky dark to the west, but now you can see that Mars has moved slightly to the south. Ain’t celestial mechanics grand?!
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Tonight we’ll head back to Scorpius to have a look at three pristine open clusters. Begin your starhop at the colorful southern Zeta pair and head north less than one degree for NGC 6231 (Right Ascension: 16 : 54.0 - Declination: -41 : 48).
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Wonderfully bright in binoculars and well resolved to the telescope, this tight open cluster was first discovered by Hodierna before 1654. De Cheseaux cataloged it as object 9, Lacaille as II.13, Dunlop as 499, Melotte as 153, and Collinder as 315. No matter what catalog number you chose to put in your notes, you’ll find the 3.2 million year young cluster shining as the “Northern Jewelbox!” For high power fans, look for the brightest star in this group – it’s van den Bos 1833, a splendid binary.
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About another degree north is loose open cluster Collinder 316, with its stars scattered widely across the sky. Caught on its eastern edge is another cluster known as Trumpler 24, a site where new variables might be found. This entire region is encased in a 90 arc minute faint emission nebula called IC 4628 (Right Ascension: 16 : 57.0 - Declination: -40 : 20) – making this low power journey through southern Scorpius a red hot summer treat!
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<b>Thursday, August 16</b> – If you did not get a chance to look at the Northern Jewelbox region in Scorpius, return again and sweep the area tonight. For those with larger telescopes, we’re going to hop about a degree and a half south of twin Nu for NGC 6242 (Right Ascension: 16 : 55.6 - Declination: -39 : 30).
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Discovered by Lacaille and cataloged as I.4, it is also known as Dunlop 520, Melotte 155 and Collinder 317. At roughly magnitude 6, this open cluster is within binocular range, but truly needs a telescope to appreciate its fainter stars. While NGC 6242 might seem like nothing more than a pretty little cluster with a bright double star, it contains an x-ray binary which is a “runaway” black hole. It is surmised that it formed near the galactic center and was vaulted into an eccentric orbit when the progenitor star exploded. Its kinetic energy is much like a neutron star or a millisecond pulsar, and it was the first black hole confirmed to be in motion.
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Now head a little more than a degree east-southeast for NGC 6268 (Right Ascension: 17 : 02.4 - Declination: -39 : 44). At a rough magnitude of 9, this small open cluster can be easily observed in smaller scopes and resolved in larger ones. The cluster itself is somewhat lopsided, with more of its members concentrated on the western half of its borders. While it, too, might not seem particularly interesting, this young cluster is highly evolved and contains some magnetic, chemically peculiar stars and Be class, or metal-weak, members.
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<b>Friday, August 17</b> – Today in 1966 Pioneer 7 was launched. It was the second in a series of satellites sent to monitor the solar wind, and study cosmic rays, interplanetary space, and magnetic fields. If you’re out early, be sure to take a look for the close pairing of Mars and Saturn and Spica. If you’ve had the opportunity to view them over the last few days, you can see how quickly Mars has moved! Instead of being in a line, the trio now… well… triangulates!
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Tonight it’s New Moon! Let’s return to previous study star Lambda Scorpii and hop three fingerwidths northeast… We’re re-hunting the “Butterfly!”
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Easily seen in binoculars and tremendous in the telescope, this brilliant magnitude 4 open cluster was first discovered by Hodierna before 1654 and independently discovered by de Cheseaux as his object 1, before being cataloged by Messier as M6 (Right Ascension: 17 : 40.1 - Declination: -32 : 13). Containing around 80 stars, the light you see tonight left its home in space around the year 473 A.D. It is believed to be around 95 million years old and contains a single yellow supergiant – the variable BM Scorpii. While most of M6′s stars are hot, blue main sequence, the unique shape of this cluster gives it not only visual appeal, but wonderful color contrast as well!
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Now let’s head towards more unusual open clusters – this time in Cygnus. Starting with Gamma Cygni, locate a loose cluster involving Gamma, Do (Dolidze) 43. Now shift two degrees southwest to pick up Do 42 as well. Don’t confuse Do 42 with nearby M29 though, for the two look very similar. For fans of the “Double Cluster” in Perseus, you’ll like the next pairing! Shift another half degree southwest along the body of Cygnus to pick out Do 40 and Do 41. This pretty pair can be placed in the same low power field. By moving another half degree due west, you’ll find highly populated Do 39 and that, too, is a double treat. The brighter clump of stars in the same low power field is IC 4996 (Right Ascension: 20 : 16.5 - Declination: +37 : 38).
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Now for two bright open clusters. The first, Ruprecht 173 is about a degree northwest of Epsilon Cygni. You’ll truly appreciate this heavily populated star cluster! The next is as easy as identifying the constellation of Lyra. Just southeast of bright Vega is a wonderful double for binoculars, Delta 1 and 2 – the easternmost most two stars in the lyre. This bright pair is part of an open cluster known as Stephenson 1.
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<b>Saturday, August 18</b> – On this day in 1868, Norman Lockyer was very busy as he was the first to see helium absorption lines in the Sun’s spectrum. Tonight we’ll take a walk from helium rich Lambda Scorpii about three fingerwidths east-northeast to an even more prominent area of stars that was known to Ptolemy as far back as 130 AD.
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Astronomers throughout the ages have spent time with this cluster: Hodierna as Ha II.2; Halley in 1678 as number 29, Derham in 1733 as number 16, De Cheseaux as number 10, Lacaille as II.14; Bode as 41; once for William Herschel and again for John as h 3710; Dreyer as NGC 6475… But we know it best as Messier Object 7 (Right Ascension: 17 : 53.9 - Declination: -34 : 49).
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Set against the backdrop of the Milky Way, even the smallest of binoculars will enjoy this bright open cluster while telescopes can resolve its 80 members. Roughly 800 light-years away, it contains many different spectral types in various stages of evolution, giving the cluster an apparent age of about 260 million years. Full of binaries and close doubles, an extreme test of tonight’s lighting conditions would be to see if you can spot the 11th magnitude globular cluster NGC 6453 (Right Ascension: 17 : 50.9 - Declination: -34 : 36) to the northwest!
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And for last, the densely populated open cluster M11 (Right Ascension: 18 : 51.1 - Declination: -06 : 16). The “Wild Duck” cluster soars about a fist’s width northeast of M16. Dominated by a single 8th magnitude star, this conically-shaped 3,000 member assembly of stardust easily resolves into innumerable stars with any significant amount of magnification. Through intermediate aperture, this 6000 light-year distant, 250 million year old cluster takes on a new form as several hundred 13th and 14th magnitude members begin to spill outside its V-shaped bounds! Discovered by Gottfried Kirch of Berlin observatory in 1681, the cluster was first noted as stellar by William Derham in the first third of the 18th century. Charles Messier added it to his catalog May 30, 1764.
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<b>Sunday, August 19</b> – Born today in 1646, let’s have a look at John Flamsteed. He was an English astronomer with a passion for what he did. Despite a rather difficult childhood and no formal education, he went on to become the First Observer at the Royal Observatory and his catalog of 3000 stars was perhaps the most accurate yet published. Flamsteed star numbers are still in use. Also born on this day was Orville Wright, in 1871, and in 1891, Milton Humason, a colleague of Edwin Hubble at Mts. Wilson and Palomar. The latter was instrumental in measuring the faint spectra of galaxies, which in turn provided evidence for the expansion of the Universe.
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This would be a great time for us to have a look at one of the summer’s most curious galaxies – NGC 6822 (Right Ascension: 19 : 44.9 - Declination: -14 : 48). This study is a telescopic challenge even for skilled observers. Set your sights roughly 2 degrees northeast of easy double 54 Sagittarii, and have a look at this distant dwarf galaxy bound to our own Milky Way by invisible gravitational attraction…
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Named after its discoverer (E. E. Barnard – 1884), “Barnard’s Galaxy” is a not-so-nearby member of our local galaxy group. Discovered with a 6″ refractor, this 1.7 million light-year distant galaxy is not easily found, but can be seen with very dark sky conditions and at the lowest possible power. Due to large apparent size, and overall faintness (magnitude 9), low power is essential in larger telescopes to give a better sense of the galaxy’s frontier. Observers using large scopes will see faint regions of glowing gas (HII regions) and unresolved concentrations of bright stars. To distinguish them, try a nebula filter to enhance the HII and downplay the star fields. Barnard’s Galaxy appears like a very faint open cluster overlaid with a sheen of nebulosity, but the practiced eye using the above technique will clearly see that the “shine” behind the stars is extragalactic in nature.
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Now look less than a degree north-northwest to turn up pale blue-green NGC 6818 (Right Ascension: 19 : 44.0 - Declination: -14 : 09) – the “Little Gem” planetary. Easily found in any size scope, this bright and condensed nebula reveals its annular nature in larger scopes but hints at it in scopes as small as 6″. Use a super wide field long-focus eyepiece to frame them both!
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Until next week? Wishing you clear skies!
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<i>Written by Tammy Plotner</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-4872716752962118782012-08-05T16:25:00.000-07:002012-08-05T16:25:44.694-07:00Weekly SkyWatcher's Forecast: August 6-12, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! While you start your observing week out by watching the Mars Curiosity Landing, be sure to step outside and view the Aquarid meteor shower, too! It's going to be a grand week for globular cluster studies and breezing along the Milky Way. Whenever you're ready to learn some more history, mystery and just plain fun things about the night sky, then meet me in the back yard... <a name='more'></a>
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<b>Monday, August 6</b> – Today in 2001 the Galileo spacecraft made its flyby of Jupiter’s moon - Io -sending back incredible images of the surface. For southern hemisphere observers, be on watch as the Iota Aquarid meteor shower peaks on this Universal date.
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Tonight our studies of globular clusters continues as we look deeper into structure. As a rule, globular clusters normally contain a large number of variable stars, and most are usually the RR Lyrae type such as in earlier study M54. At one time they were known as “cluster variables,” with their number differing from one globular to another. Many globulars also contain vast numbers of white dwarfs. Some have neutron stars which are detected as pulsars, but out of all 151, only four have planetary nebulae in them.
Now, let us head toward the emerging constellation of Pegasus and the magnitude 6.5, class IV M15 (Right Ascension: 21 : 30.0 - Declination: +12 : 10). Easily located with even small binoculars about four degrees northwest of Enif, this magnificent globular cluster is a true delight in a telescope. Amongst the globulars, M15 ranks third in variable star population with 112 identified. As one of the densest of clusters, it is surprising that it is considered to be only class III. Its deeply concentrated core is easily apparent, and has begun the process of core collapse. The central core itself is very small compared to the cluster’s true size and almost half M15′s mass is contained within it. Although it has been studied by the Hubble, we still do not know if this density is caused by the cluster stars’ mutual gravity, or if it might disguise a supermassive object similar to those in galactic nuclei.
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M15 was the first globular cluster in which a planetary nebula, known as Pease 1, could be identified. Larger aperture scopes can easily see it at high power. Surprisingly, M15 also is home to 9 known pulsars, which are neutron stars left behind from previous supernovae during the cluster’s evolution, and one of these is a double neutron star. While total resolution is impossible, a handful of bright stars can be picked out against that magnificent core region and wonderful chains and streams of members await your investigation tonight!
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<b>Tuesday, August 7</b> – On this date in 1959, Explorer 6 became the first satellite to transmit photographs of the Earth from its orbit.
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Tonight, let’s return again to look at two giant globular clusters roughly equal in size, but not equal in class. To judge them fairly, you must use the same eyepiece. Start first by re-locating previous study M4. This is a class IX globular cluster. Notice the powder-like qualities. It might be heavily populated, but it is not dense. Now return to previous study M13. This is a class V globular cluster. Most telescopes will make out at least some resolution and a distinct core region. It is the level of condensation that determines the class. It is no different from judging magnitudes and simply takes practice.
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Try your hand at M55 (Right Ascension:19 : 40.0 - Declination: -30 : 58) along the bottom of the Sagittarius “teapot” – it’s a class XI. Although it is a full magnitude brighter than class I M75, which we looked at earlier in the week, can you tell the difference in concentration? For those with GoTo systems, take a quick hop through Ophiuchus and look at the difference between NGC 6356 (class II) and NGC 6426 (class IX). If you want to try one that they can’t even classify? Look no further than M71 (Right Ascension: 19 : 53.8 - Declination: +18 : 47) in Sagitta. It’s all a wonderful game and the most fun comes from learning!
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In the meantime, don’t forget all those other wonderful globular clusters such as 47 Tucanae, Omega Centauri, M56, M92, M28 and a host of others!
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<b>Wednesday, August 8</b> – Today in 2001, the Genesis Solar Particle Sample Return mission was launched. In September of 2004, it crash landed in the Utah desert with its precious payload. Although some of the specimens were contaminated, some did survive the mishap. So what is “star stuff?” Mostly highly charged particles generated from a star’s upper atmosphere and flowing out in a state of matter known as plasma…
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Tonight let’s study one of the grandest of all solar winds as we seek out an area about three fingerwidths above the Sagittarius “teapot’s spout” as we have a look at magnificent M8 (Right Ascension: 18 : 03.8 - Declination: -24 : 23), the “Lagoon Nebula.”
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Visible to the unaided eye as a hazy spot in the Milky Way, fantastic in binoculars, and an area truly worth study in any size scope, this 5200 light-year area of emission, reflection and dark nebulae has a rich history. Its involved star cluster – NGC 6530 – was first discovered by Flamsteed around 1680, and the nebula by Le Gentil in 1747. Cataloged by Lacaille as III.14 about 12 years before Messier listed it as number 8, its brightest region was recorded by John Herschel and the dark nebulae were discovered by Barnard.
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Tremendous areas of starbirth are taking place in this region; while young, hot stars excite the gases in a are known as the “Hourglass,” around Herschel star 36 and 9 Sagittarius. Look closely around cluster NGC 6530 for Barnard dark nebulae B89 and B296 at the nebula’s southern edge. No matter how long you chose to swim in the “Lagoon” you will sure find more and more things to delight both the mind and the eye!
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<b>Thursday, August 9</b> – Today in 1976, the Luna 24 mission was launched on a return mission of its own – not to retrieve solar winds samples, but lunar soil! Remember this mission as we take a look at its landing site in the weeks ahead.
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Tonight we’ll return to the nebula hunt as we head about a fingerwidth north and just slightly west of M8 for the “Trifid”…
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M20 (Right Ascension: 18 : 02.3 - Declination: -23 : 02) was discovered by Messier on June 5, 1764, and much to his credit, he described it as a cluster of stars encased in nebulosity. This is truly a wonderful observation since the Trifid could not have been easy given his equipment. Some 20 years later William Herschel (although he usually avoided repeating Messier objects) found M20 of enough interest to assign separate designations to parts of this nebula – IV.41, V.10, V.11, V.12. The word “Trifid” was used to describe its beauty by John Herschel.
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While M20 is a very tough call in binoculars, it is not impossible with good conditions to see the light of an area that left its home nearly a millennium ago. Even smaller scopes will pick up this round, hazy patch of both emission and reflection, but you will need aversion to see the dark nebula which divides it. This was cataloged by Barnard as B85. Larger telescopes will find the Trifid as one of the very few objects that actually appears much in the eyepiece as it does in photographs – with each lobe containing beautiful details, rifts and folds best seen at lower powers. Look for its cruciform star cluster and its fueling multiple system while you enjoy this triple treat tonight!
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<b>Friday, August 10</b> – Today in 1966 Lunar Orbiter 1 was successfully launched on its mission to survey the Moon. In the weeks ahead, we’ll take a look at what this mission sent back!
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Tonight we’ll look at another star forming region as we head about a palm’s width north of the lid star (Lambda) in the Sagittarius teapot as we seek out “Omega”…
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Easily viewed in binoculars of any size and outstanding in every telescope, the 5000 light-year distant Omega Nebula was first discovered by Philippe Loys de Cheseaux in 1745-46 and later (1764) cataloged by Messier as object 17. This beautiful emission nebula is the product of hot gases excited by the radiation of newly born stars. As part of a vast region of interstellar matter, many of its embedded stars don’t show in photographs, but reveal themselves beautifully to the eye of the telescope. As you look at its unique shape, you realize that many of these areas are obscured by dark dust, and this same dust is often illuminated by the stars themselves.
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Often known as the “Swan,” M17 (Right Ascension: 18 : 20.8 - Declination: -16 : 11) will appear as a huge, glowing check mark or ghostly “2″ in the sky – but power up if you use a larger telescope and look for a long, bright streak across its northern edge, with extensions to both the east and north. While the illuminating stars are truly hidden, you will see many glittering points in the structure itself and at least 35 of them are true members of this region spanning about 40 light-years that could contain up to 800 solar masses. It is awesome…
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<b>Saturday, August 11</b> – On this date in 1877, Asaph Hall of the U.S. Naval Observatory was very busy. This night would be the first time he would see Mars’ outer satellite Deimos! Six nights later, he observed Phobos, giving Mars its grand total of two moons.
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Tonight after midnight is the peak of the Perseid meteor shower, and this year there’s not so much Moon to contend with! Now let’s sit back and talk about the Perseids while we watch…
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The Perseids are undoubtedly the most famous of all meteor showers and never fail to provide an impressive display. Their activity appears in Chinese history as far back as 36 AD. In 1839, Eduard Heis was the first observer to give an hourly count, and discovered their maximum rate was around 160 per hour at that time. He, and other observers, continued their studies in subsequent years to find that this number varied.
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Giovanni Schiaparelli was the first to relate the orbit of the Perseids to periodic comet Swift-Tuttle (1862 III). The fall rates have both risen and fallen over the years as the Perseid stream was studied more deeply, and many complex variations were discovered. There are actually four individual streams derived from the comet’s 120 year orbital period which peak on slightly different nights, but tonight through tomorrow morning at dawn is our accepted peak.
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Meteors from this shower enter Earth’s atmosphere at a speed of 60 km/sec (134,000 miles per hour), from the general direction of the border between the constellations Perseus and Cassiopeia. While they can be seen anywhere in the sky, if you extend their paths backward, all the true members of the stream will point back to this region of the sky. For best success, position yourself so you are generally facing northeast and get comfortable. If you are clouded out, don’t worry. The Perseids will be around for a few more days yet, so continue to keep watch!
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And speaking of watching… If you’re out late, be sure to watch for a Jupiter/Moon conjunction. What an inspiring bit of sky scenery to watch them rise together! For lucky viewers in the Indonesia area, this is an occultation event, so please be sure to check resources for times and locations in your area.
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<b>Sunday, August 12</b> – Did you mark your calendar to be up before dawn to view the Perseid meteor shower? Good!
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Tonight while dark skies are on our side, we’ll fly with the “Eagle” as we hop another fingerwidth north of M17 and head for one of the most famous areas of starbirth – IC 4703.
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While the open cluster NGC 6611 was first discovered by Cheseaux in 1745-6, it was Charles Messier who cataloged the object as M16 and he was the first to note the nebula IC 4703 (Right Ascension: 18 : 18.9 - Declination: -13 : 47), more commonly known as the “Eagle.” At 7000 light-years distant, this roughly 7th magnitude cluster and nebula can be spotted in binoculars, but at best it is a hint. As part of the same giant cloud of gas and dust as neighboring M17, the Eagle is also a place of starbirth illuminated by these hot, high energy stellar youngsters which are only about five and a half million years old.
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In small to mid-sized telescopes, the cluster of around 20 brighter stars comes alive with a faint nebulosity that tends to be brighter in three areas. For larger telescopes, low power is essential. With good conditions, it is very possible to see areas of dark obscuration and the wonderful “notch” where the Pillars of Creation lie. Immortalized by the Hubble Space telescope, you won’t see them as grand or colorful as it did, but what a thrill to know they are there!
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Until next week? Clear skies!
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<i>Written by Tammy Plotner. Image Credit: Globular Cluster M15 from Hubble - Credit: ESA, Hubble, NASA</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-66093503698915370382012-08-02T07:21:00.002-07:002012-08-02T07:21:54.145-07:00Swirling Along With NGC 1187<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLSIjiVHOMBcHXOjzFtTNBjbAxjV4PwpyqGdx5rUcep-TomB5qa1BHzmhJqm4EeubIKHZpsIJVIWJ2GUAlH9Sq5dV-2VJM5SLgotY5LPjsK-_Z7j26pmtbUvpsXoLSoCqh76f1ul58qMvL/s1600/ngc1187.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="232" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLSIjiVHOMBcHXOjzFtTNBjbAxjV4PwpyqGdx5rUcep-TomB5qa1BHzmhJqm4EeubIKHZpsIJVIWJ2GUAlH9Sq5dV-2VJM5SLgotY5LPjsK-_Z7j26pmtbUvpsXoLSoCqh76f1ul58qMvL/s400/ngc1187.jpg" /></a></div>
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Discovered by Sir William Herschel in 1784, galaxy NGC 1187 floats along 60 million light-years away in the river Eridanus. It looks as peaceful as a cool, blue whirlpool... but, is all really quiet? Not hardly. This nearly face-on spiral galaxy is home to some very violent action - like two major supernova events in the last thirty years. Now, thanks to ESO’s Very Large Telescope, we're able to examine all of its facets in one of the most detailed photographs ever taken. <a name='more'></a>
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At its heart beats a bulging yellow glow. Here is the home of ancient stars, caught in cobwebs of old gas and dust. Look closely, the nucleus is round, but slightly elongated - the tell-tale sign of a central bar structure. This formation is considered to be a sort of funnel that pushes gas from the spiral arms towards the core and enriches star formation. The arms themselves have blue and pink inclusions - areas rich in star clusters counterpointed by regions forming new stars. However, sometimes stars die, don't they? Yes, they do.
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And they don't die quietly.
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Since 1982, this calm little galaxy has experienced two supernova events - a violent explosion of either a massive star or a white dwarf in a binary system. During this time they can briefly outshine their host galaxy and linger on for months before fading away. Going down in a blaze of glory? You betcha'. A supernova event is so powerful that the energy expended in that brief moment equals the amount of energy expended by most stars during their entire lifetime!
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<center><div id='flashplayer'>Loading player...</div><script type='text/javascript' src='http://www.eso.org/public/archives/djangoplicity/shadowbox3/libraries/mediaplayer5/jwplayer.js'></script><script type='text/javascript'>var sdfile = 'http://www.eso.org/public/archives/videos/medium_flash/eso1231a.flv';var imagefile = 'http://www.eso.org/public/archives/videos/videoframe/eso1231a.jpg';var flashsrc = 'http://www.eso.org/public/archives/djangoplicity/shadowbox3/libraries/mediaplayer5/player.swf';var sharelink = 'http://www.eso.org/public/videos/eso1231a/';var sharecode = '';var gaid = 'UA-1965004-1';var ipadfile = 'http://www.eso.org/public/archives/videos/medium_podcast/eso1231a.m4v';var mobilefile = 'http://www.eso.org/public/archives/videos/medium_podcast/eso1231a.m4v';var hdfile = 'http://www.eso.org/public/archives/videos/hd_and_apple/eso1231a.m4v';;</script><script type='text/javascript' src='http://www.eso.org/public/archives/djangoplicity/js/videoembed.js'></script></center>
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In October 1982, the first supernova seen in NGC 1187 - SN 1982R - was discovered at La Silla Observatory. It wasn't just an ordinary supernova - it was surmised to be a core collapse in a disturbed galaxy. "When the galaxies are split into `disturbed' and `undisturbed' categories, a striking difference emerges. The disturbed galaxies have a central excess of core-collapse supernovae, and this excess is almost completely dominated by supernovae of types Ib, Ic and Ib/c, whereas type II supernovae dominate in all other environments." says S.M. Habergham (et al). "The difference cannot easily be explained by metallicity or extinction effects, and thus we propose that this is direct evidence for a stellar initial mass function that is strongly weighted towards high mass stars, specifically in the central regions of disturbed galaxies."
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Are their findings correct? Quite possibly. In 2007, the amateur astronomer Berto Monard in South Africa spotted another supernova in this galaxy - SN 2007Y - and it wasn't ordinary either. It was thought to be a core collapse of a helium-rich star. "The oxygen abundance suggests that the progenitor was most likely a ≈3.3 M sun He core star that evolved from a zero-age-main-sequence mass of 10-13 M sun." says M. Stritzinger (et al). "SN 2007Y is among the least energetic normal Type Ib SNe ever studied."
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Better to burn out than to fade away? Look again, because there's more to the picture than meets the eye. SN 2007Y may have been the least energetic ever studied, but it ain't gone yet. The supernova can still be seen - long after the time of maximum brightness - near the bottom of the image.
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Hey, hey... my, my. Rock and roll will never die.
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<i>Written by Tammy Plotner. Original Story Source: <a href="http://www.eso.org/public/news/eso1231/" target="blank">ESO News Release</a>. Image Credit: ESO’s Very Large Telescope at the Paranal Observatory in Chile. Video Credit: ESO/A. Fujii/Digitized Sky Survey 2. Acknowledgment: Davide De Martin. Music: Disasterpeace</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-27229148390839739802012-07-31T02:50:00.000-07:002012-07-31T02:50:07.111-07:00Weekly SkyWatcher's Forecast: July 30 - August 5, 2012<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMGYMZdPKDIr88wpJI64Q60N4HYsSHrF9rpqvUKstKqOeP8JH5G1y08zNwSF2qe5LLvgZ9bHBpeEofG3DhxD1mio-7128GJ6qzwS-tm5ty-H6d2bZlpQPAGaKqQTwr2l9-qKwQGaGJGWFZ/s1600/jherschel_damien_peach.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="301" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMGYMZdPKDIr88wpJI64Q60N4HYsSHrF9rpqvUKstKqOeP8JH5G1y08zNwSF2qe5LLvgZ9bHBpeEofG3DhxD1mio-7128GJ6qzwS-tm5ty-H6d2bZlpQPAGaKqQTwr2l9-qKwQGaGJGWFZ/s400/jherschel_damien_peach.jpg" /></a></div>
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Greetings, fellow SkyWatchers! It's big. It's bright. There's no escaping it. This week the Moon will be our major point of study, but don't rule out some bright globular clusters and interesting stars! There's plenty of history and science to explore, too. Whenever you're ready, just meet me in the back yard... <a name='more'></a>
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<b>Monday, July 30</b> – Today’s history celebrates the 2001 flyby of the Moon by the Wilkinson Microwave Anisotropy Probe (WMAP) on its way to Lagrange Point 2 to study the cosmic microwave background radiation.
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Now that we're back at Sinus Iridum on the lunar surface, we'll hop across Mare Frigoris and northeast of the punctuation of Harpalus for a grand old crater - J. Herschel. Although it looks small because it is seen on the curve, this wonderful old walled plain named for John Herschel contains some very tiny details. Its southeastern rim forms the edge of Mare Frigoris and the small (24 km) Horrebow dots its southwest edge. The crater walls are so eroded with time that not much remains of the original structure. Look for many very small telescopic impact craters which dot J. Herschel's uneven basin and exterior edges. Power up! If you can spot the small central crater C, you are resolving a feature only 12 kilometers wide from some 385,000 kilometers away! Formed in the Pre-Nectarian period, this walled plain could be as much as 4 billion years old...
Now, relax and enjoy the peak of the Capricornid meteor shower. Although it is hard for the casual observer to distinguish these meteors from the Delta Aquarids, no one minds. Again, face southeast and enjoy! The fall rate for this shower is around 10 to 35 per hour, but unlike the Aquarids, this stream produces those great “fireballs” known as bolides. Enjoy…
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<b>Tuesday, July 31</b> – Tonight on the Moon, look south of Mare Humorum is darker Paulus Epidemiarum eastward and paler Lacus Excellentiae westward. To their south you will see a complex cojoined series of craters we'll take a closer look at - Hainzel and Mee. Hainzel was named for Tycho Brahe's assistant and measures about 70 kilometers in length and sports several various interior wall structures. Power up and look. Hainzel's once high walls were obliterated on the north-east by the strike that caused Hainzel C and to the north by impact which caused the formation of Hainzel A. To its basic south is eroded Mee - named for a Scottish astronomer. While Crater Mee doesn't appear to be much more than simple scenery, it spans 172 kilometers and is far older than Hainzel. While you can spot it easily in binoculars, close telescope inspection shows how the crater is completely deformed by Hainzel. Its once high walls have collapsed to the northwest and its floor is destroyed. Can you spot small impact crater Mee E on the northern edge?
Now, let’s take the opportunity to look at two multiple star systems – Nu and Xi Scorpii.
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Starting with Nu about a fingerwidth east and slightly north of bright Beta, we find a handsome duo of stars in a field of nebulosity that will challenge telescopic observers much the way that Epsilon Lyrae does. With any small telescope, the observer will easily see the widely separated A and C stars. Add just a little power and take your time… The C star has a D companion to the southwest! For larger telescopes, take a very close look at the primary star. Can you separate the B companion to the south?
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Now let’s hop to Xi about four fingerwidths north of Beta.
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Discovered by Sir William Herschel in 1782, this 80 light-year distant system poses a nice challenge for mid-sized scopes. The yellow-hued A and B pair share a very eccentric orbit about the same distance as Uranus is from our Sun. During the 2007 observing year they should be fairly well spaced, and the slightly fainter secondary should appear to the north. Look a good distance away for the 7th magnitude orange C component and south for yet another closely-matched double of 7th and 8th magnitude – the D and E stars.
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For the larger scope, this multiple star system does display a little bit of color. Most will see the A and B components as yellow/white, the C star as slightly orange, and the D/E pair as slightly tinged with blue. Be sure to mark your observations for this is one of the finest!
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<b>Wednesday, August 1</b> – Today is the birthdate of Maria Mitchell. Born in 1818, Mitchell became the first woman to be elected as an astronomer to the American Academy of Arts and Sciences. She later rocketed to worldwide fame when she discovered a bright comet in 1847.
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For larger telescopes, let's try a challenging lunar study worthy of your observing skills. Due west of Hansteen you will find a small crater known as Sirsalis near the terminator. It will appear as a small, dark ellipse with a bright west wall along with its twin, Sirsalis B. The feature you will be looking for is the Sirsalis Rille - the longest lunar "wrinkle" presently known. Stretching northeast of Sirsalis and ex-tending 459 kilometers south to the bright rays of Byrgius, this major "crack" in the lunar surface shows several branchings - like a long dry river bed. Geologically forming in the Imbrian period, chances are the Sirsalis Rille is lunar graben. Thanks to Lunar Orbiter images, the evidence points to shifting tectonic plates as the source of this incredible feature.
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Tonight, let’s continue our exploration of globular clusters. These gravitationally bound concentrations of stars contain anywhere from ten thousand to one million members and attain sizes of up to 200 light-years in diameter. At one time, these fantastic members of our galactic halo were believed to be round nebulae. Perhaps the very first to be discovered was M22 in by Abraham Ihle in 1665. This particular globular is easily seen in even small binoculars and can be located just slightly more than two degrees northeast of the “teapot’s lid,” Lambda Sagittarii.
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Ranking third amongst the 151 known globular clusters in total light, M22 (Right Ascension: 18 : 36.4 - Declination: -23 : 54) is probably the nearest of these incredible systems to our Earth with an approximate distance of 9600 light-years, and it is also one of the nearest globulars to the galactic plane. Since it resides less than a degree from the ecliptic, it often shares the same eyepiece field with a planet. At magnitude 6, the class VII M22 will begin to show individual stars to even modest instruments and will burst into stunning resolution for larger aperture. About a degree west-northwest, mid-sized telescopes and larger binoculars will capture smaller 8th magnitude NGC 6642. At class V, this particular globular will show more concentration toward the core region than M22. Enjoy them both!
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<b>Thursday, August 2</b> – Tonight we’ll fly right by the Full Buck Moon as we continue our studies to have a look at Mu 1 and Mu 2 Scorpii about two fingerwidths north of Zeta.
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Very close to the same magnitude and spectral type, the twin Mu stars are easy to separate visually and most definitely worth a look in telescopes or binoculars. They are considered an actual physical pair because they share the exact same distance and proper motion, but they are separated by less than one light-year.
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Hanging out in space some 520 light-years away, western Mu 1 is a spectroscopic binary – the very first discovered to have double lines. This Beta Lyrae-type star has an orbiting companion that eclipses it around every day and a half, yet causes no significant visual drop in magnitude – even though the orbiting companion is only 10 million kilometers away from it! While that sounds like plenty of distance, when the two pass, their surfaces would nearly touch each other!
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<b>Friday, August 3</b> – Tonight let’s race ahead of the rising Moon as we continue our studies with one of the globulars nearest to the galactic center – M14 (Right Ascension: 17 : 37.6 - Declination: -03 : 15). Located about sixteen degrees (less than a handspan) south of Alpha Ophiuchi, this ninth magnitude, class VIII cluster can be spotted with larger binoculars, but will only be fully appreciated with the telescope.
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When studied spectroscopically, globular clusters are found to be much lower in heavy element abundance than stars such as own Sun. These earlier generation stars (Population II) began their formation during the birth of our galaxy, making globular clusters the oldest of formations that we can study. In comparison, the disk stars have evolved many times, going through cycles of starbirth and supernovae, which in turn enrich the heavy element concentration in star forming clouds and may cause their collapse. Of course, as you may have guessed, M14 breaks the rules. It contains an unusually high number of variable stars – in excess of 70 – with many of them known to be the W Virginis type. In 1938, a nova appeared in M14, but it was undiscovered until 1964 when Amelia Wehlau of the University of Ontario was surveying the photographic plates taken by Helen Sawyer Hogg. The nova was revealed on eight of these plates taken on consecutive nights, and showed itself as a 16th magnitude star – and was believed to be at one time almost 5 times brighter than the cluster members. Unlike 80 years earlier with T Scorpii in M80, actual photographic evidence of the event existed. In 1991, the eyes of the Hubble were turned its way, but neither the suspect star nor traces of a nebulous remnant were discovered. Then six years later, a carbon star was discovered in M14.
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To a small telescope, M14 will offer little to no resolution and will appear almost like an elliptical galaxy, lacking in any central condensation. Larger scopes will show hints of resolution, with a gradual fading towards the cluster’s slightly oblate edges. A true beauty!
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<b>Saturday, August 4</b> – As we explore globular clusters, we simply assume them all to be part of the Milky Way galaxy, but that might not always be the case. We know they are basically concentrated around the galactic center, but there may be four of them that actually belong to another galaxy. Tonight we’ll look at one such cluster being drawn into the Milky Way’s halo. Set your sights just about one and a half degrees west-southwest of Zeta Sagittarii for M54 (Right Ascension: 18 : 55.1 - Declination: -30 : 29).
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At around magnitude 7.6, M54 is definitely bright enough to be spotted in binoculars, but its rich class III concentration is more notable in a telescope. Despite its brightness and deeply concentrated core, M54 isn’t exactly easy to resolve. At one time we thought it to be around 65,000 light-years distant, and rich in variables – with 82 known RR Lyrae types. We knew it was receding, but when the Sagittarius Dwarf Elliptical Galaxy was discovered in 1994, it was noted that M54 was receding at almost precisely the same speed! When more accurate distances were measured, we found M54 to coincide with the SagDEG distance of 80-90,000 light-years, and M54′s distance is now calculated to be 87,400 light-years. No wonder it’s hard to resolve – it’s outside our galaxy!
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As we know, most globular clusters congregate around the galactic center in the Ophiuchus/Sagittarius region. Tonight let’s explore what creates a globular cluster’s form… We’ll start with the “head of the class,” M75 (Right Ascension: 20 : 06.1 - Declination: -21 : 55).
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Orbiting the galactic center for billions of years, globular clusters endured a wide variety of disturbances. Their component stars escape when accelerated by mutual encounters and the tidal force of our own Milky Way pulls them apart when they are near periapsis, that is, closest to the galactic center. Even close encounters with other masses, such as other clusters and nebulae, can affect them! At the same time, their stellar members are also evolving and this loss of gas can contribute to mass loss and deflation of these magnificent clusters. Although this happens far less quickly than in open clusters, our observable globular friends may only be the survivors of a once larger population, whose stars have been spread throughout the halo. This destruction process is never-ending, and it is believed that globular clusters will cease to exist in about 10 billion years.
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Although it will be later evening when M75 appears on the Sagittarius/Capricornus border, you will find the journey of about 8 degrees southwest of Beta Capricorni worth the wait. At magnitude 8, it can be glimpsed as a small round patch in binoculars, but a telescope is needed to see its true glory. Residing around 67,500 light-years from our solar system, M75 is one of the more remote of Messier’s globular clusters. Since it is so far from the galactic center – possibly 100,000 light-years distant – M75 has survived almost intact for billions of years to remain one of the few Class I globular clusters. Although resolution is possible in very large scopes, note that this globular cluster is one of the most concentrated in the sky, with only the outlying stars resolvable to most instruments.
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<b>Sunday, August 5</b> – Today we celebrate the birthday of Neil Armstrong, the first human to walk on the Moon. Congratulations! Also on this date in 1864, Giovanni Donati made the very first spectroscopic observations of a comet (Tempel, 1864 II). His observations of three absorption lines led to what we now know as the Swan bands, from a form of the carbon radical C2.
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Our study continues tonight as we move away from the galactic center in search of a remote globular cluster that can be viewed by most telescopes. As we have learned, radial velocity measurements show us the majority of globulars are involved in highly eccentric elliptical orbits, which take them far outside the plane of the Milky Way. These orbits form a sort of spherical “halo” which tends to be more concentrated toward our galactic center. Reaching out several thousands of light-years, this halo is actually larger than the disk of our own galaxy. Since globular clusters aren’t involved in our galaxy’s disk rotation, they may possess very high relative velocities. Tonight let’s head toward the constellation of Aquila and look at one such globular – NGC 7006 (Right Ascension: 21 : 01.5 - Declination: +16 : 11).
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Located about half a fist’s width east of Gamma Aquilae, NGC 7006 is speeding towards us at a velocity of around 345 kilometers per second. At 150,000 light-years from the center of our galaxy, this particular globular could very well be an extra-galactic object. At magnitude 11.5, it’s not for the faint of heart, but can be spotted in scopes as small as 150mm, and requires larger aperture to look like anything more than a suggestion. Given its tremendous distance from the galactic center, it’s not hard to realize this is a class I – although it is quite faint. Even the largest of amateur scopes will find it unresolvable!
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Until next week? May all your skies by clear and steady...
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<i>Written by Tammy Plotner. Image Credit: Crater J. Herschel Courtesy of Damian Peach</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-65366973283323360972012-07-22T15:41:00.000-07:002012-07-22T15:41:47.550-07:00Weekly SkyWatcher's Forecast: July 23-29, 2012<div class="separator" style="clear: both; text-align: center;">
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Greetings, fellow SkyWatchers! Are you ready for a week filled with alternative astronomical observing studies? If so, you'll enjoy looking at some unusual stars and star clusters. If you want to keep things cool, then come along as we mine for lunar ice. Feeling a bit more lazy? Then kick back and enjoy the Delta Aquarid meteor shower or just step out after sunset and enjoy a splendid conjunction! It's all here... Just head outside! <a name='more'></a>
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<b>Monday, July 23</b> – Tonight we’ll launch our imaginations as we view the area around Mare Crisium and have a look at this month’s lunar challenge – Macrobius. You’ll find it just northwest of the Crisium shore. Spanning 64 kilometers in diameter, this Class I impact crater drops to a depth of nearly 3600 meters – about the same as many of our earthly mines. Its central peak rises up 1100 meters, and may be visible as a small speck inside the crater’s interior. Be sure to mark your lunar challenges and look for other features you may have missed before!
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Now, relax and let’s talk until the Moon sets…
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As we know most stars begin life in stellar nurseries and end life either alone or in very small groups as doubles or multiple stars. Tonight we can have a look at a group of young stars beginning their stellar evolution and end with an old solitary elder preparing to move on to an even “higher realm.” Open cluster IC 4665 (Right Ascension: 17 : 46.3 - Declination: +05 : 43) is easily detected with just about any optical aid about a finger-width north-northeast of Beta Ophiuchi. Discovered by Philippe Loys de Cheseaux in the mid-1700s, this 1400 light-year distant cluster consists of about 30 mixed magnitude stars all less than 40 million years of age. Despite its early discovery, the cluster did not achieve broad enough recognition for Dreyer to include it in the late 19th century New General Catalog and it was later added as a supplement to the NGC in the Index Catalog of 1908. Be sure to use low power to so see all of this large group.
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About three finger-widths north-northeast of IC 4665 is a study that did make Dreyer’s catalogue – NGC 6572 (Right Ascension: 18 : 12.1 - Declination: +06 : 51). This 9th magnitude planetary is very small – but intense. Like the “Cat’s Eye” in Draco, and NGC 6210 in Hercules, this planetary can take a lot of magnification. Those with large scopes should look for a small, round, blue inner core encased is a faint shell. A challenge to find? You bet. Worth the work? Sometimes working for something makes it all the more fun!
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<b>Tuesday, July 24</b> – As our observing evening begins, be sure to look for one of the finest conjunctions of the year! Hovering around the waxing crescent Moon like bees drawn to a hive, you’ll find Mars to the upper right and Spica to the upper left (northwest and northeast respectively). To Spica’s upper right, you’ll find Saturn joining the show, too! This is a very “photogenic” opportunity...
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With plenty of Moon to explore tonight, why don’t we try locating an area where many lunar exploration missions made their mark? Binoculars will easily reveal the fully disclosed areas of Mare Serenitatis and Mare Tranquillitatis, and it is where these two vast lava plains converge that we will set our sights. Telescopically, you will see a bright “peninsula” westward of where the two conjoin which extends toward the east. Just off that look for bright and small crater Pliny. It is near this rather inconspicuous feature that the remains Ranger 6 lie forever preserved where it crashed on February 2, 1964.
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Unfortunately, technical errors occurred and it was never able to transmit lunar pictures. Not so Ranger 8! On a very successful mission to the same relative area, this time we received 7137 “postcards from the Moon” in the last 23 minutes before hard landing. On the “softer” side, Surveyor 5 also touched down near this area safely after two days of malfunctions on September 10, 1967. Incredibly enough, the tiny Surveyor 5 endured temperatures of up to 283 degrees F, but was able to spectrographically analyze the area’s soil… And by the way, it also managed to televise an incredible 18,006 frames of “home movies” from its distant lunar locale.
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<b>Wednesday, July 25</b> – Today in 1971, Apollo 15 was launched on its way towards the Moon, and we’ll continue our celebration of space exploration and walk on the Moon where the first man set foot. For SkyWatchers, the dark round area you see on the northeastern limb is Mare Crisium and the dark area below that is Mare Fecunditatis. Now look mid-way on the terminator for the dark area that is Mare Tranquillitatis. At its southwest edge, history was made.
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In binoculars, trace along the terminator where the Caucasus Mountains stand – and then south for the Apennines and the Haemus Mountains. As you continue towards the center of the Moon, you will see where the shore of Mare Serenitatis curves east, and also the bright ring of Pliny. Continue south along the terminator until you spot the small, bright ring of Dionysius along the edge of Mare Tranquillitatis. Just to the southwest, you may be able to see the soft rings of Sabine and Ritter. It is near here where the base section of the Apollo 11 landing module – Eagle – lies forever enshrined in “magnificent desolation.”
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For telescope users, the time is now to power up! See if you can spot small craters Armstrong, Aldrin and Collins just east. Even if you cannot, the Apollo 11 landing area is about the same distance as Sabine and Ritter are wide to the east-southeast. Even if you don’t have the opportunity to see it tonight, take the time during the next couple of days to point it out to your children, grandchildren, or even just a friend… The Moon is a spectacular world and we’ve been there!
Tonight let’s have a look with our eyes first at Delta Ophiuchi. Known as Yed Prior (“The Hand”), look for its optical double Epsilon to the southeast: Yed Posterior. Now have a look in binoculars or a telescope at absolute minimum power for another undiscovered gem…
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Delta Ophiuchi is 170 light-years from us, while Epsilon is 108 – but look at the magnificent field they share. Stars of every spectral type are in an area of sky which could easily be covered by a small coin held at arm’s length. Enjoy this fantastic field – from the hot, blue youngsters to the old red giants!
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<b>Thursday, July 26</b> – Long before the Sun sets, look for the Moon to appear in the still-blue sky. As it darkens, watch for shadows on the surface. Have you ever wondered if there was any place on the lunar surface that hasn’t seen the sunlight? Then let’s go searching for one tonight…
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Our first order of business will be to identify crater Albategnius. Directly in the center of the Moon is a dark floored area known as Sinus Medii. South of it will be two conspicuously large craters – Hipparchus to the north and ancient Albategnius to the south. Trace along the terminator toward the south until you have almost reached its point (cusp) and you will see a black oval. This normal looking crater with the brilliant west wall is equally ancient crater Curtius. Because of its high southern latitude, we shall never see the interior of this crater – and neither has the Sun! It is believed that the inner walls are quite steep and that Curtius’ interior has never been illuminated since its formation billions of years ago. Because it has remained dark, we can speculate that there may be “lunar ice” pocketed inside its many cracks and rilles that date back to the Moon’s formation!
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Because our Moon has no atmosphere, the entire surface is exposed to the vacuum of space. When sunlit, the surface reaches up to 385 K, so any exposed “ice” would vaporize and be lost because the Moon’s gravity cannot hold it. The only way for “ice” to exist would be in a permanently shadowed area. Near Curtius is the Moon’s south pole, and the Clementine spacecraft’s imaging showed around 15,000 square kilometers in which such conditions could exist. So where did this “ice” come from? The lunar surface never ceases to be pelted by meteorites – most of which contain water ice. As we know, many craters were formed by just such impacts. Once hidden from the sunlight, this “ice” could remain for millions of years!
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<b>Friday, July 27</b> – Tonight let’s skip the Moon and take a look at an astounding system called 36 Ophiuchi, located about a thumb’s width southeast of Theta. Situated in space less than 20 light-years from Earth, even small telescopes can split this pair of 5th magnitude K type giants very similar to our own Sun, and larger telescopes can also pick up the C component as well. 36 Ophiuchi B is also known as system 544…because it has what could very likely be a planet in a habitable zone!
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Now we’ll have a look at a beautifully contrasting pair of stars – Zeta 1 and 2 Scorpii. You’ll find them a little less than a handspan south-southeast of Antares and at the western corner of the J of the constellation’s shape.
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Although the two Zetas aren’t a true physical pair, they are nonetheless interesting. The easternmost, orange sub-giant Zeta 2 appears far brighter for a reason… It’s much closer at only 155 light-years away. But, focus your attention on western Zeta 1. It’s a blue supergiant that’s around 5700 light-years away and shines with the light of 100,000 suns and exceeds even Rigel in sheer power! The colorful pair is easily visible as two separate stars to the unaided eye, but a real delight in binoculars or a low power telescope field. Check them out tonight!
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<b>Saturday, July 28</b> – Tonight let’s continue our studies of the lunar poles by returning to previous study crater Plato. North of Plato you will see a long horizontal area with a gray floor – Mare Frigoris. North of it you will note a double crater. This elongated diamond-shape is Goldschmidt and the crater which cuts across its western border is Anaxagoras. The lunar north pole isn’t far from Goldschmidt, and since Anaxagoras is just about one degree outside of the Moon’s theoretical “arctic circle” the lunar sun will never go high enough to clear the southernmost rim.
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On March 5, 1998, NASA announced that Lunar Prospector’s neutron spectrometer data showed that water ice had been discovered at both lunar poles. The first results showed the ice was mixed in with lunar regolith (soil, rocks and dust), but long term data confirmed near pure pockets hidden beneath about 40 cm of surface material – with the results being strongest in the northern polar region. It is estimated there may be as much as 6 trillion kg (6.6 billion tons) of this valuable resource! If this still doesn’t get your motor running, then realize that without it, we could never establish a manned lunar base because of the tremendous expense involved in transporting our most basic human need – water.
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The presence of lunar water could also mean a source of oxygen, another vital material we need to survive! And for returning home or voyaging further, these same deposits could provide hydrogen which could be used as rocket fuel. So as you view Anaxagoras tonight, realize that you may be viewing one of mankind’s future “homes” on a distant world!
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Now grab a comfortable seat because the Delta Aquarid meteor shower reaches its peak tonight. It is not considered a prolific shower, and the average fall rate is about 25 per hour – but who wouldn’t want to take a chance on observing a meteor about every 4 to 5 minutes? These travelers are considered to be quite slow, with speeds around 24 kilometers per second and are known to leave yellow trails. One of the most endearing qualities of this annual shower is its broad stream of around 20 days before and 20 days after peak. This will allow it to continue for at least another week and overlap the beginning stages of the famous Perseids.
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The Delta Aquarid stream is a complicated one, and a mystery not quite yet solved. It is possible that gravity split the stream from a single comet into two parts, and each may very well be a separate stream. One thing we know for certain is they will seem to emanate from the area around Capricornus and Aquarius, so you will have best luck facing southeast and getting away from city lights. Although the Moon will interfere, just relax and enjoy a warm summer night. It’s time to catch a “falling star!”
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<b>Sunday, July 29</b> – Tonight let’s take an entirely different view of the Moon as we do a little “mountain climbing!” The most outstanding feature on the Moon will be the emerging Copernicus, but since we’ve delved into the deepest areas of the lunar surface, why not climb to some of its peaks?
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Using Copernicus as our guide, to the north and northwest of this ancient crater lie the Carpathian Mountains, ringing the southern edge of Mare Imbrium. As you can see, they begin well east of the terminator, but look into the shadow! Extending some 40 kilometers beyond the line of daylight, you will continue to see bright peaks – some of which reach 2072 meters high! When the area is fully revealed tomorrow, you will see the Carpathian Mountains eventually disappear into the lava flow that once formed them. Continuing onward to Plato, which sits on the northern shore of Imbrium, we will look for the singular peak of Pico. It is between Plato and Mons Pico that you will find the scattered peaks of the Teneriffe Mountains. It is possible that these are the remnants of much taller summits of a once stronger range, but only around 1890 meters still survives above the surface.
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Time to power up! Lather, rinse and repeat until you know these by heart… To the west of the Teneriffes, and very near the terminator, you will see a narrow series of hills cutting through the region west-southwest of Plato. This is known as the Straight Range – Montes Recti – and some of its peaks reach up to 2072 meters. Although this doesn’t sound particularly impressive, that’s over twice as tall as the Vosges Mountains in central Europe and on the average very comparable to the Appalachian Mountains in the eastern United States. Not bad!
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Now head about a palm’s width east of our previous study star - Zeta Scorpii - for lovely Theta. Named Sargas, this 1.8 magnitude star resides around 650 light-years distant in a very impressive field of stars for binoculars or a small telescope. While all of these are only optical companions, the field itself is worth a look – and worth remembering for the future.
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About three fingerwidths north is true double Lambda Scorpii, also known as Shaula (The Sting). As the brightest known star in its class, 1.6 magnitude Lambda is a spectroscopic binary which is also a variable of the Beta Canis Majoris type, changing ever so slightly in little more than 5 hours. Although we can’t see the companion star, nearby is yet another that will make learning this starhop “marker” worth your time.
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Until next week? Ask for the Moon, but keep on reaching for the stars!
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<i>Written by Tammy Plotner. Image - IC 4665 - Credit: Palomar Observatory, courtesy of Caltech</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-60517435999216407782012-07-19T12:02:00.000-07:002012-07-19T12:04:14.162-07:00Titan's Seasons Do The Twist<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8LyENEEYRCaWq944ha8Kj6BUxXhVXTNfVYqJRGYR51dVPcaJEzwby6GoWvVxnfOkmExbIJZyD8Cca0JCX6XQVUkekQI-3IJuvXEqGpGOsy6BZnl_hpDcScc_OWmiG576uuaBt4XYmw2Eq/s1600/twist1.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="290" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8LyENEEYRCaWq944ha8Kj6BUxXhVXTNfVYqJRGYR51dVPcaJEzwby6GoWvVxnfOkmExbIJZyD8Cca0JCX6XQVUkekQI-3IJuvXEqGpGOsy6BZnl_hpDcScc_OWmiG576uuaBt4XYmw2Eq/s400/twist1.jpg" /></a></div>
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"You should see my little Sis. She really knows how to rock. She knows how to twist!" And so does a vortex which has appeared at the southern pole of Saturn's moon, Titan. It's a sign that the seasons are changing! Thanks to images taken with NASA's Cassini spacecraft, we're able to join in the dance. <a name='more'></a>
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“The structure inside the vortex is reminiscent of the open cellular convection that is often seen over Earth’s oceans,” said Tony Del Genio, a Cassini team member at NASA’s Goddard Institute for Space Studies, N.Y. “But unlike on Earth, where such layers are just above the surface, this one is at very high altitude, maybe a response of Titan’s stratosphere to seasonal cooling as southern winter approaches. But so soon in the game, we’re not sure.”
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Cassini originally spotted a “hood” of high-altitude haze - along with a vortex - when it first arrived at Saturn in 2004. This swirling gas around the pole has been monitored by several instruments which have been keeping watch for signs of changing seasons - most notably the southern winter. The northern "hood" has remained and the upper atmosphere has been trekking from the highlighted north pole to the cooling south. Apparently this movement is causing "downwellings" over the southern pole - the reasons for the appearance of high-altitude haze and the vortex.
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“We’ve been watching this vortex become more developed in the last three to four months, and now, captured in exquisite detail, we’re seeing finer scale features within the detached haze than have been seen to date,” said Jason Perry, an imaging team associate at the University of Arizona, Tucson.
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Cassini’s visible light cameras was the first to pick out the beginning haze starting to well over Titan’s south pole in March, and the spacecraft’s visual and infrared mapping spectrometer (VIMS) obtained false-color images on May 22 and June 7.
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3l7lr0B4BMU73ylc29jok0Ce0eJ1gHPF_3NUy8UUF3pUn2lUexhv0lTmuLg788qFrIzI-ZDl6pBkXuR_8sas9eizC0qo8eqsQsJswRIv9aE9TSvz9-zxSvCdtwgAYVi2lvV6UOTAxXfPn/s1600/twist2.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="323" width="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3l7lr0B4BMU73ylc29jok0Ce0eJ1gHPF_3NUy8UUF3pUn2lUexhv0lTmuLg788qFrIzI-ZDl6pBkXuR_8sas9eizC0qo8eqsQsJswRIv9aE9TSvz9-zxSvCdtwgAYVi2lvV6UOTAxXfPn/s400/twist2.gif" /></a></div>“VIMS has seen a concentration of aerosols forming about 200 miles [300 kilometers] above the surface of Titan’s south pole,” said Christophe Sotin, a VIMS team member at NASA’s Jet Propulsion Laboratory, Pasadena, California. “We’ve never seen aerosols here at this level before, so we know this is something new.” What's more, on June 27 during a distant flyby, Cassini’s imaging cameras caught a great view vortex over the south pole of the south in visible light... and in unsurpassed detail.
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“Future observations of this feature will provide good tests of dynamical models of the upper atmosphere,” said Bob West, deputy imaging team lead at JPL.
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Thanks to Cassini’s newly inclined orbits - the next phase of Cassini Solstice Mission - the new, detailed images may soon become commonplace. Up until now, Cassini was orbiting the equatorial plane and the previous images of the polar vortex were taken from above Titan’s equator. These images revealed changes in the haze layer on the limb over the south polar region.
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“I believe we are seeing some fascinating events on the way to the formation of the south polar vortex, said West. “Future observations of this feature will provide good tests of dynamical models of the Titan circulation, chemistry, cloud and aerosol processes in the upper atmosphere.”
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And I believe we'll all be watching. "Come on little Sis... Do the twist!"
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<i>Submitted by Tammy Plotner. Original Story and Image Source: <a href="http://saturn.jpl.nasa.gov/index.cfm" target="blank">JPL/NASA News Release - Cassini Solstice Mission</a>.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-1880886346670626362012-07-15T17:02:00.000-07:002012-07-15T17:03:36.125-07:00Weekly SkyWatcher's Forecast: July 16-22, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/07/m19.jpg"><img class="size-medium wp-image-96299" src="http://www.universetoday.com/wp-content/uploads/2012/07/m19-580x565.jpg" alt="" width="580" height="565" /></a>
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<center><i>Messier 19 - Credit: Doug Williams, REU Program/NOAO/AURA/NSF</i></center>
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Greetings, fellow SkyWatchers! My satellite dish and internet connection has now returned from the land of Oz. While it was great to have a span of days where no electric meant no annoying lights, it also meant creative cooking excursions on the gas grill in 100 degree weather. Ah, well... the things we do for dark skies! This is New Moon week, so get out there and enjoy the Milky Way! Whenever you're ready, meet me in the back yard... <a name='more'></a>
<strong>Monday, July 16</strong> – Today in 1850 at Harvard University, the first photograph of a star (other than the Sun) was made. The honors went to Vega! In 1994, an impact event was about to happen as nearly two dozen fragments of Comet Shoemaker-Levy 9 were speeding their way to the surface of Jupiter. The result was spectacular, and the visible features left behind on the planet’s atmosphere were the finest ever recorded.
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Now let’s return again to the oblate and beautiful M19 and drop two fingerwidths south for another misshapen globular – M62 (Right Ascension: 17 : 01.2 - Declination: -30 : 07).
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At magnitude 6, this 22,500 light-year distant Class IV cluster can be spotted in binoculars, but comes to wonderful life in the telescope. First discovered by Messier in 1771, Herschel was the first to resolve it and report on its deformation. Because it is so near to the galactic center, tidal forces have “crushed” it – much like M19. You will note when studying in the telescope that its core is very off center. Unlike M19, M62 has at least 89 known variable stars – 85 more than its neighbor – and the dense core may have undergone collapse. A large number of X-ray binaries have also been discovered within its structure, perhaps caused by the close proximity of stellar members. Enjoy it tonight!
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<strong>Tuesday, July 17</strong> – If you’re up to another challenge tonight, let’s go hunting Herschel I.44, also known as NGC 6401. You’ll find this 9.5 magnitude globular cluster around two fingerwidths northeast of Theta Ophiuchi and a little more than a degree due east of star 51 (Right Ascension: 17 : 38.6 - Declination: -23 : 55).
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Discovered by William Herschel in 1784 and often classed as “uncertain,” today’s powerful telescopes have placed this halo object as a Class VIII and given it a rough distance from the galactic center of 8,800 light-years. Although neither William nor John could resolve this globular, and they listed it originally as a bright nebula, studies in 1977 revealed a nearby suspected planetary nebula named Peterson 1. Thirteen years later, further study revealed this to be a symbiotic star.
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Symbiotic stars are a true rarity – not a singular star at all, but a binary system. A red giant dumps mass towards a white dwarf in the form of an accretion disc. When this reaches critical mass, it then causes a thermonuclear explosion resulting in a planetary nebula. While no evidence exists that this phenomenon is physically located within metal-rich NGC 6401, just being able to see it in the same field makes this journey both unique and exciting!
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<strong>Wednesday, July 18</strong> – On this day 27 years ago, India launched its first satellite (Rohini 1), and 31 years ago in the United States Gemini 10 launched carrying John Young and Michael Collins to space.
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Now, let’s carry ourselves into space as we take a very unusual and beautiful journey to a bright and very colorful pair of stars known as Omicron 1 Cygni. Easily located about halfway between Alpha (Deneb) and Delta on the western side, this is a pure delight in binoculars or any size telescope. The striking gold color of 3.7 magnitude 31 Cygni (Omicron 1) is easily highlighted against the blue of same field companion, 5th magnitude 30 Cygni. Although this wide pairing is only an optical one, the K-type giant is a double star – an eclipsing variable around 150 times larger than or own Sun – and is surrounded by a gaseous corona more than double the size as the star itself. If you are using a scope, you can easy spot the blue tinted, 7th magnitude B star about one third the distance as between the two giants. Although our true pair are some 1.2 billion miles apart, they are oriented nearly edge-on from our point of view – allowing the smaller star to be totally eclipsed during each revolution. This total eclipse lasts for 63 days and happens about every 10.4 years, but don’t stay up too late… We’ve still got 7 years to wait!
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<strong>Thursday, July 19</strong> – Today in 1846, Edward Pickering was born. Although his name is not well known, he became a pioneer in the field of spectroscopy. Pickering was the Harvard College Observatory Director from 1876 to 1919, and it was during his time there that photography and astronomy began to merge. Known as the Harvard Plate Collection, these archived beginnings still remain a valuable source of data.
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It’s New Moon, so why not have a look at something that would make Edward Pickering proud? He enthusiastically encouraged amateur astronomers, and founded the American Association of Variable Star Observers – so set your sights on RR Scorpius about two fingerwidths northeast of Eta and less than a fingerwidth southwest M62 (RA 16 56 37.84 Dec -30 34 48.2). This very red Mira type can reach as high as magnitude 5 and drop as low as 12 in about 280 days!
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Tonight let’s just enjoy a little stargazing and revel in the beauty of our own galaxy’s spiral arm – the Milky Way. For those living in the city, you owe it to yourself to get away to a dark location to enjoy this veritable “river of stars” which spans out of the galactic center south and runs overhead. Almost directly behind you from the galactic anti-center stretches the Perseus arm, and the sight is a beautiful one. If skies are fine, you can easily see the dark dust rift where the arm separates and the billows of light of unresolved stars. It’s the most glorious sight of summer! While we have many days yet before the Aquarid meteor shower officially reaches its peak, you will be pleasantly surprised at this year’s high activity. They’ve been flying out of the night sky for almost two weeks now, and it would not surprise me if you saw ten or more per hour of these quick, bright visitors.
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<strong>Friday, July 20</strong> – Today was a busy day in astronomy history! In 1969, the world held its breath as the Apollo 11 lander touched down and Neil Armstrong and Edwin Aldrin became the first humans to touch the lunar surface. We celebrate our very humanity because even Armstrong was so moved that he messed up his lines! The famous words were meant to be “A small step for a man. A giant leap for mankind.” That’s nothing more than one small error for a man, and mankind’s success continued on July 20, 1976 when Viking 1 landed on Mars – sending back the first images ever taken from that planet’s surface.
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If you’re out at sunset, be sure to look for the slimmest crescent Moon you can imagine… It will point your way to nearby Mercury! For lucky viewers “down under” this is an occultation event and will only be observable after sunset from southernmost regions of central Australia. Be sure to check the resources for websites like IOTA for specific times and locations.
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The first assignment of the evening is a pair of interacting galaxies. 40? northwest of Beta Canum Venaticorum is NGC 4490 (Right Ascension: 12 : 30.6 - Declination: +41 : 38) and smaller, fainter companion NGC 4485 (Right Ascension: 12 : 30.5 - Declination: +41 : 42). This pair, also known as Arp 269, are quite unusual in appearance to the larger scope. NGC 4490 is around magnitude 10 and shows a bright, irregular core region and a rather strange profile. Known as the “Cocoon” galaxy, it appears to almost reach toward its companion 3? to the north. Progressively larger scopes under ideal conditions will be able to make out some faint mottling in the NGC 4490's structure.
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Now let’s honor southern skies by exploring the fantastic, NGC 3372 (Right Ascension: 10 : 43.8 - Declination: -59 : 52) – the Eta Carinae Nebula. As a giant, diffuse nebula with a visual brightness of magnitude 1, (wow!) it contains the most massive and luminous star in our Milky Way galaxy, Eta Carinae. It’s also home to a small cluster, Collinder 228, which is only one of 8 cataloged open clusters within the area of this huge star-forming region; the others are Bochum (Bo) 10, Trumpler (Tr) 14 (also cataloged as Cr 230), Tr 15 (= Cr 231), Cr 232, Tr 16 (= Cr 233), Cr 234, and Bo 11. Star Eta Carinae is involved in open cluster Trumpler 16. This fantastic nebula contains details which northerners can only dream about, such as the dark “Keyhole” and the “Homunkulus” around the giant star itself. A fantastic region for exploration with both telescopes and binoculars!
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<strong>Saturday, July 21</strong> – Today in 1961, Mercury 4 was launched, sending Gus Grissom into suborbital space on the second manned flight, and he returned safely in Liberty Bell 7.
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Since the moonlight will now begin to interfere with our early evening globular cluster studies, let’s waive them for a while as we take a look at some of the region’s most beautiful stars. Tonight your goal is to locate Omicron Ophiuchi, about a fingerwidth northeast of Theta. At a distance of 360 light-years, this system is easily split by even small telescopes. The primary star is slightly dimmer than magnitude 5 and appears yellow to the eye. The secondary is near 7th magnitude and tends to be more orange in color. This wonderful star is part of many double star observing lists, so be sure to note it!
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Tonight would be an ideal time to look at a brilliant open cluster about a fist width east of Epsilon Scorpii – M6 (Right Ascension: 17 : 40.1 - Declination: -32 : 13). On a moonless night, the 50 or so members of this 2000 light year distant, 100 million year old cluster can usually be seen unaided as a small fuzzy patch just above the Scorpion’s tail. Tonight we visit because the brighter skies will aid you in seeing the primary stars distinctive asterism. Using binoculars or telescope at lowest power, the outline of stars does truly resemble its namesake – the “Butterfly Cluster”. The M6 is much more than “just a pretty face” and we’ll be back to study under darker skies.
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<strong>Sunday, July 22</strong> – Tonight instead of lunar exploration, we will note the work of Friedrich Bessel, who was born on this day in 1784. Bessel was a German astronomer and mathematician whose functions, used in many areas of mathematical physics, still carry his name. But, you may put away your calculator, because Bessel was also the very first person to measure a star’s parallax. In 1837, he chose 61 Cygni and the result was no more than a third of an arc second. His work ended a debate that had stretched back two millennia to Aristotle’s time and the Greek’s theories about the distances to the stars.
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Although you’ll need to use your finderscope with tonight’s brighter skies, you’ll easily locate 61 between Deneb (Alpha) and Zeta on the eastern side. Look for a small trio of stars and choose the westernmost. Not only is it famous because of Bessel’s work, but it is one of the most noteworthy of double stars for a small telescope. 61 Cygni is the fourth nearest star to Earth, with only Alpha Centauri, Sirius, and Epsilon Eridani closer. Just how close is it? Try right around 11 light-years.
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Visually, the two components have a slightly orange tint, are less than a magnitude apart in brightness and have a nice separation of around 30? to the south-southeast. Back in 1792, Piazzi first noticed 61?s abnormally large proper motion and dubbed it “The Flying Star.” At that time, it was only separated by around 10? and the B star was to the northeast. It takes nearly 7 centuries for the pair to orbit each other, but there is another curiosity here. Orbiting the A star around every 4.8 years is an unseen body that is believed to be about 8 times larger than Jupiter. A star – or a planet? With a mass considerably smaller than any known star, chances are good that when you view 61 Cygni, you’re looking toward a distant world!
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Until next week, dreams really do come true when you keep on reaching for the stars!
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<i>Written by Tammy Plotner</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-87513933465142030892012-07-11T18:05:00.000-07:002012-07-11T18:05:04.952-07:00Hubble Reveals Fifth Moon Of Pluto<div class="separator" style="clear: both; text-align: center;">
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Through the incredible eye of NASA’s Hubble Space Telescope, a team of astronomers have announced the revelation of a another moon orbiting the icy dwarf planet Pluto. The moon is incredibly tiny - only about 6 to 15 miles in diameter - and irregularly shaped. It would appear to be in a 58,000 mile diameter orbit around Pluto and assumed to be co-planar with the other satellites in the system. This brings the known number of moons orbiting Pluto to five. How exciting is that?! <a name='more'></a>
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“The moons form a series of neatly nested orbits, a bit like Russian dolls,” said team lead Mark Showalter of the SETI Institute in Mountain View, California.
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The Pluto team members consist of M. Showalter (SETI Institute), H.A. Weaver (Applied Physics Laboratory, Johns Hopkins University), and S.A. Stern, A.J. Steffl, and M.W. Buie (Southwest Research Institute). This group is mystified that a dwarf planet could harbor such a complex collection of satellites. Through this new discovery, they may eventually be able to understand how a Plutonian system could form and evolve. At the present, the conjecture is the system may have formed through a collision with a Kuiper belt object during the solar system's early years.
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Thanks to Hubble, the researchers are able to paint a far more accurate portrait of the environs which NASA's New Horizons spacecraft will encounter in 2015. This high-speed flyby will be an historic event and revealing potential navigational hazards in advance will ultimately lead to a successful mission. New Horizons will be blazing past the system at a speed of 30,000 miles per hour and encountering even a seed-sized piece of debris could spell disaster.
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“The discovery of so many small moons indirectly tells us that there must be lots of small particles lurking unseen in the Pluto system,” said Harold Weaver of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
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“The inventory of the Pluto system we’re taking now with Hubble will help the New Horizons team design a safer trajectory for the spacecraft,” added Alan Stern of the Southwest Research Institute in Boulder, Colorado, the mission’s principal investigator.
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Pluto’s largest moon, Charon, was discovered in 1978 in observations made at the United States Naval Observatory in Washington, D.C. Hubble observations in 2006 uncovered two additional small moons, Nix and Hydra. In 2011 another moon, P4, was found in Hubble data. Provisionally designated S/2012 (134340) 1, the latest moon was detected in nine separate sets of images taken by Hubble’s Wide Field Camera 3 on June 26, 27, 29, and July 3 and 9.
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After New Horizons completes its Pluto flyby, astronomers will utilize the infrared vision of NASA’s James Webb Space Telescope to make additional observations. The Webb telescope will go even further into exploration by measuring the surface chemistry of Pluto, its moons, and many other bodies that lie in the distant Kuiper Belt along with Pluto.
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For a little world that's no longer a planet, it's still making big news!
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<i>Reported by Tammy Plotner. Original Story Source: <a href="http://hubblesite.org/newscenter/archive/releases/2012/32/full/" target="blank">JPL/NASA Hubble News Release</a>.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-17147376583730756022012-06-25T12:01:00.000-07:002012-06-25T12:01:08.009-07:00Weekly SkyWatcher's Forecast: June 25 - July 1, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/06/Julius_Caesar_07-15-06_S240ip4.jpg"><img src="http://www.universetoday.com/wp-content/uploads/2012/06/Julius_Caesar_07-15-06_S240ip4-580x403.jpg" alt="" width="580" height="403" class="size-medium wp-image-95963" /></a>
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Greetings, fellow SkyWatchers! What a great week to enjoy lunar features! We'll celebrate many famous birthdays - including Charles Messier - and take on challenging double stars. If you're in the mood to just kick back in a lawn chair and enjoy, then check out the June Draconid meteor shower. (sssssh... it may have been responsible for the Tunguska Blast!) Still more? Then keep an eye on the western horizon, because Mercury is about to become a "guest star" in the Beehive Cluster! When ever you're ready, just meet me in the back yard... <a name='more'></a>
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<b>Monday, June 25</b> – Today celebrates the birth of Hermann Oberth – who has often been considered the father of modern rocketry. Born in Transylvania in 1894, Oberth was a visionary who was convinced space travel would one day be possible. Inspired by the works of Jules Verne, Oberth studied rockets and wrote many books devoted to the possibility of achieving spaceflight. He was the first to conceive of rocket “stages” – allowing vehicles to expend their fuel and lose dead weight. But tonight you won’t need one of Oberth’s rockets to travel to the Moon, as take on another challenge as we look mid-way along the terminator at the west shore of Mare Tranquillitatis for crater Julius Caesar.
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This is also a ruined crater, but it met its demise not through lava flow - but from a cataclysmic event. The crater is 88 kilometers long and 73 kilometers wide. Although its west wall still stands over 1200 meters high, look carefully at the east and south walls. At one time, something plowed its way across the lunar surface, breaking down Julius Caesar's walls and leaving them to stand no higher than 600 meters at the tallest. While visiting the "Tranquil Sea", look for the unusually shaped crater Hypatia. Can you spot its rima on the southern shore of Tranquillitatis? Perhaps the bright pockmark of Moltke on its north edge will help. Hypatia sits on the northern shore of a rugged area known as Sinus Asperitatis. Do you see Alfraganus on the terminator? Follow the terrain to Theophilus and look west for Ibyn-Rushd with crater Kant to the northwest and the beautiful peak of Mons Penck to its east.
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<b>Tuesday, June 26</b> – On this day in 1949, asteroid Icarus was discovered on a 48-inch Schmidt plate made nine months after that telescope went into operation, and just prior to the beginning of the multi-year National Geographic-Palomar Sky Survey. The asteroid was found to have a highly eccentric orbit and a perihelion distance of just 27 million kilometers, closer to the Sun than Mercury, giving it its unusual name. It was just 6.4 million kilometers from Earth at the time of discovery, and variations in its orbital parameters have been used to determine Mercury’s mass and test Einstein’s theory of general relativity.
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But, today is even more special because it is the birthday of none other than Charles Messier, the famed French comet hunter. Born in 1730, Messier is best known for cataloging the 100 or so bright nebulae and star clusters that we now refer to as the Messier objects. The catalog was intended to keep both Messier and others from confusing these stationary objects with possible new comets.
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If you missed your chance last night to see the incredible Alpine Valley, it's now fully disclosed in the sunlight. Viewable through binoculars as a thin, dark line, telescopic observers at highest powers will enjoy a wealth of details in this area, such as a crack running inside its boundaries. It's a wonderful lunar observing challenge and a guide to our next lunar feature - Cassini and Cassini A. Where the valley joins the lunar Alps, follow the range south into Mare Imbrium. Along the way you will see the protruding bright peaks of Mons Blanc, Promontorium DeVille, and at the very end, Promontorium Agassiz ending in the smooth sands. Southeast of Agassiz you will spot Cassini. The major crater spans 57 kilometers and reaches a floor depth of 1240 meters. The challenge is to also spot the central crater A, which is only 17 kilometers wide, yet drops down another 2830 meters below the surface. This shallow crater holds another challenge within - Cassini A. But look carefully, can you spot the B crater on Cassini's inner southwestern rim? Or the very small M crater just outside the northern edge?
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For more advanced lunar observers, head a bit further south to the Haemus Mountains to look for the bright punctuation of a small crater on the southwest shore of Mare Serenitatis. Increase your magnification and look for a curious feature with an even more curious name... Rima Sulpicius Gallus. It is nothing more than a lunar wrinkle which accompanies the crater of the same name - a long-gone Roman counselor. Can you trace its 90 kilometer length?
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Now see how many Messier objects that you can capture and wish Charles a happy birthday!
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<b>Wednesday, June 27</b> – Let's begin our lunar studies tonight with a little "mountain climbing!" Using Copernicus as our guide, to the north and northwest of this ancient crater lie the Carpathian Mountains ringing the southern edge of Mare Imbrium. As you can see, they begin well east of the terminator, but look into the shadow! Extending some 40 kilometers beyond the line of daylight, you will continue to see bright peaks - some of which reach a height of 2072 meters. When the area is fully revealed tomorrow, you will see the Carpathian Mountains disappear into the lava flow that once formed them.
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Let's try looking just south of Sinus Medii and identifying these features: (1) Flammarion, (2) Herschel, (3) Ptolemaeus, (4) Alphonsus, (5) Davy, (6) Alpetragius, (7) Arzachel, (8) Thebit, (9) Purbach, (10) Lacaille, (11) Blanchinus, (12) Delaunay, (13) Faye, (14) Donati, (15) Airy, (16) Argelander, (17) Vogel, (18) Parrot, (19) Klein, (20) Albategnius, (21) Muller, (22) Halley, (23) Horrocks, (24) Hipparchus, (25) Sinus Medii
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When skies are dark, it’s time to have a look at the 250 light-year distant silicon star Iota Librae. This is a real challenge for binoculars – but not because the components are so close. In Iota’s case, the near 5th magnitude primary simply overshadows its 9th magnitude companion! In 1782, Sir William Herschel measured them and determined them to be a true physical pair. Yet, in 1940 Librae A was determined to have an equal magnitude companion only .2 arc seconds away…. And the secondary was proved to have a companion of its own that echoes the primary. A four star system!
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While you’re out, keep watch for a handful of meteors originating near the constellation of Corvus. The Corvid meteor shower is not well documented, but you might spot as many as ten per hour.
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<b>Thursday, June 28</b> – Tonight on the lunar surface, use crater Copernicus as a guide and look north-northwest to survey the Carpathian Mountains. The Carpathians ring the southern edge of Mare Imbrium beginning well east of the terminator. But let's look on the dark side. Extending some 40 km beyond into the Moon's own shadow, you can continue to see bright peaks - some reaching 2000 meters high! Tomorrow, when this area is fully revealed, you will see the Carpathians begin to disappear into the lava flow forming them. Continuing northward to Plato - on the northern shore of Mare Imbrium - re-identify the singular peak of Pico. Between Plato and Mons Pico you will find the many scattered peaks of the Teneriffe Mountains. It is possible that these are the remnants of much taller summits of a once precipitous range. Now the peaks rise less than 2000 meters above the surface.
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Time to power up! West of the Teneriffes, and very near the terminator, you will see a narrow line of mountains, very similar in size to the Alpine Valley. This is known as the Straight Range or the Montes Recti. To binoculars or small scopes at low power, this isolated strip of mountains will appear as a white line drawn across the grey mare. It is believed this feature may be all that is left of a crater wall from the Imbrium impact. It runs for a distance of around 90 kilometers, and is approximately 15 kilometers wide. Some of its peaks reach as high as 2072 meters! Although this doesn't sound particularly impressive, that's over twice as tall as the Vosges Mountains in west-central Europe, and on the average very comparable to the Appalachian Mountains in the eastern United States.
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When you’re finished with your lunar observations, tonight let’s try a challenging double star – Upsilon Librae. This beautiful red star is right at the limit for a small telescope, but quite worthy as the pair is a widely disparate double. Look for the 11.5 magnitude companion to the south in a very nice field of stars!
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<b>Friday, June 29</b> – Today we celebrate the birthday of George Ellery Hale, who was born in 1868. Hale was the founding father of the Mt. Wilson Observatory. Although he had no education beyond his baccalaureate in physics, he became the leading astronomer of his day. He invented the spectroheliograph, coined the word astrophysics, and founded the Astrophysical Journal and Yerkes Observatory. At the time, Mt. Wilson dominated the world of astronomy, confirming what galaxies were and verifying the expanding universe cosmology, making Mt. Wilson one of the most productive facilities ever built. When Hale went on to found Palomar Observatory, the 5-meter (200?) telescope was named for him and dedicated on June 3, 1948. It continues to be the largest telescope in the continental United States.
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It's time to head deeper toward the lunar south as we take a close look at the dark, heart-shaped region Palus Epidemiarum. Caught on its southern edge is the largely eroded Campanus with well defined Cichus to the east and Ramsden to the west. Power up in your telescope and look carefully at its smooth floors. If conditions are favorable, you will catch Rima Hesiodus cutting across its northern boundary and the crisscross pattern of Rima Ramsden in the western lobe. Can you make out a small, deep puncture mark to the northeast? It might be small, but it has a name – Marth.
Now let’s go deep south and have look at an area which once held something almost half a bright as tonight’s Moon and over four times brighter than Venus. Only one thing could light up the skies like that – a supernova. According to historical records from Europe, China, Egypt, Arabia and Japan, 1001 years ago the very first supernova event was noted. Appearing in the constellation of Lupus, it was at first believed to be a comet by the Egyptians, yet the Arabs saw it as an illuminating “star.”
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Located less than a fingerwidth northeast of Beta Lupus (RA 15 02 48.40 Dec -41 54 42.0) and a half degree east of Kappa Centaurus, no visible trace is left of a once grand event that spanned five months of observation beginning in May, and lasting until it dropped below the horizon in September, 1006. It is believed all the force created from the event was converted to energy and very little mass remains. In the area, a 17th magnitude star shows a tiny gas ring and radio source 1459-41 remains our best candidate for pinpointing this incredible event.
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<b>Saturday, June 30</b> – We start our observing evening with the beautiful Moon as we return first to the ancient and graceful landmark crater Gassendi standing at the north edge of Mare Humorum. The mare itself is around the size of the state of Arkansas and is one of the oldest of the circular maria on the visible surface. As you view the bright ring of Gassendi, look for evidence of the massive impact which may have formed Humorum. It is believed the original crater may have been in excess of 462 kilometers in diameter, indenting the lunar surface almost twice over. Over time, similar smaller strikes formed the many craters around its edges and lava flow gradually gave the area the ridge- and rille-covered floor we see tonight. Its name is the "Sea of Moisture," but look for its frozen waves in the long dry landscape.
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Caught on the north-western rim of Mare Humorum, look for crater Mersenius. It is a typical Nectarian geological formation, spanning approximately 51 miles in diameter in all directions. Power up in a telescope to look for fine features such as steep slopes supporting newer impact crater Mersenius P and tiny interior craterlet chains. Can you spot white formations and crevices along its terraced walls? How about Rimae Mersenius? Further south you'll spy tiny Liebig helping to support Mersenius D's older structure, along with its own small set of mountains known as the Rupes Liebig. Continue to follow the edge of Mare Humorum around the wall known as Rimae Doppelmayer until you reach the shallow old crater Doppelmayer. As you can see, the whole floor fractured crater has been filled with lava flow from Mare Humorum's formation, pointing to an age older than Humorum itself. Look for a shallow mountain peak in its center - there's a very good chance this peak is actually higher than the crater walls. Did this crater begin to upwell as it filled? Or did it experience some volcanic activity of its own? Take a closer look at the floor if the lighting is right to spy a small lava dome and evidence of dark pyroclastic deposits - it's a testament to what once was!
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Still got the moonlight blues? Then try your hand at a super challenging double – Mu Librae. This pair is only a magnitude apart in brightness and right at the limit for a small telescope. Up the power slowly and look for the companion just to the southwest of the primary. Good luck and mark your observation because Mu’s blues are on many observing lists!
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And out of the blue comes a meteor shower! Keep watch tonight for the June Draconids. The radiant for this shower will be near handle of Big Dipper – Ursa Major. The fall rate varies from 10 to 100 per hour, but tonight’s bright skies will toast most of the offspring of comet Pons-Winnecke. On a curious note, today in 1908 was when the great Tunguska impact happened in Siberia. A fragment of a comet, perhaps?
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<b>Sunday, July 1</b> – Today In 1917, the astronomers at Mt. Wilson were celebrating as the 100? primary mirror arrived. Up until that time, the 60? Hale telescope (donated by George Hale’s father) was the premier creation of St. Gobrain Glassworks – which was later commissioned to create the blank for the Hooker telescope. Thanks to the funds provided by John D. Hooker (and Carnegie), the dream was realized after years of hard work and ingenuity to create not only a building to properly house it – but the telescope workings as well. It saw “first light” five months later on November 1.
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As anxious astronomers waited for this groundbreaking moment, the scope was aimed at Jupiter but the image was horrible – to their dismay, workmen had left the dome open and the Sun had heated the massive mirror! Try as they might to rest until it had cooled – no astronomer slept. Fearful of the worst, sometime around three in the morning they returned again long after Jupiter had set. Pointing the massive scope towards a star, they achieved a perfect image!
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If you’re looking for a perfect image, then look no further than the western horizon tonight at twilight. Why? Because Mercury is going to be a “guest star” in the Beehive Cluster! Be sure to at least get out your binoculars and look at the speedy little inner planet as it cruises about a degree or so to the western edge of M44.
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Tonight we'll return again to our landmark lunar feature - crater Grimaldi - and begin our journey north...
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As you move north of Grimaldi on a crater hop, the next feature you will en-counter is the walled plain of Hevelius. With a diameter of about 64 miles, this round area doesn't have a height we can really measure because of its lunar position, but we can see that it does have some relatively steep walls around its edges. Hevelius was formed in the Nectarian geological period and if you look closely you'll see that it has a small central peak, a fine rimae and many craterlet chains, too. Can you spot large interior Crater Hevelius A with just binoculars? How about companion crater Cavalerius which is part of its northern border?
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While you’re out, take the time to look at lowly Theta Lupi about a fistwidth south-southwest of the mighty Antares. While this rather ordinary looking 4th magnitude star appears to be nothing special – there’s a lesson to be learned here. So often in our quest to look at the bright and incredible – the distant and the impressive – we often forget about the beauty of a single star. When you take the time to seek the path less traveled, you just might find more than you expected. Hiding behind a veil of the “ordinary” lies a trio of three spectral types and three magnitudes in a diamond-dust field. An undiscovered gem…
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Until next week? Ask for the Moon, but keep on reaching for the stars!
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<i>Written by Tammy Plotner. Many thanks to Wes Higgins and Greg Konkel for their spectacular lunar shots!</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-14486316284857147502012-06-22T07:51:00.000-07:002012-06-22T07:53:07.995-07:00NuSTAR Reveals The Universe In X-Rays<center><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvjwE8GscyUFjDoimKlE7ccHNLNdsTEUF2Wvtxiz1_dgAhhyqrav8uDBvMjGiVKp7JvpzAixEStW7V9ah1S-_AkLbF_P85iVWuGQ2HzH-AW051C_QDyw5hyEFrsv1Fyh7lv-86pdUzqkOd/s1600/nustar_nosecone_news.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="300" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvjwE8GscyUFjDoimKlE7ccHNLNdsTEUF2Wvtxiz1_dgAhhyqrav8uDBvMjGiVKp7JvpzAixEStW7V9ah1S-_AkLbF_P85iVWuGQ2HzH-AW051C_QDyw5hyEFrsv1Fyh7lv-86pdUzqkOd/s400/nustar_nosecone_news.jpg" /></a>
<h6>An Orbital Sciences technician completes final checks of NASA's NuSTAR inside the Orbital Sciences processing facility at Vandenberg Air Force Base.</h6></center>
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Over a century ago, Wilhelm Rontgen made an amazing discovery - X-rays. Never in his wildest dreams could he ever have imagined the many uses this form of electromagnetic radiation would have inspired. It has evolved from basic medical uses to the furthest reaches of outer space. Now an orbiting NASA telescope has been launched and it will provide us a look at the Universe that we've never seen before. This new telescope was developed with help from researchers from SLAC National Accelerator Laboratory and Stanford’s main campus and the views it will provide will be hard. Hard X-rays! <a name='more'></a>
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NuSTAR - the Nuclear Spectroscopic Telescope Array is the brainchild of a consortium of scientists and engineers under the leadership of Fiona Harrison from the California Institute of Technology. At its heart is a system of nested X-ray mirrors which will image the Universe in hard X-rays - the penetrating view which passes through solids, liquids and uncompressed gases. NuSTAR will be able to focus this portion of the electromagnetic spectrum into images "10 times sharper and 100 times more sensitive than any previous X-ray telescope."
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Needless to say, members of the joint SLAC/Stanford Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) are on the NuSTAR science team and are eager to get their first glimpse through this new telescope's eyes. “Every time there is a new instrument with significantly better sensitivity than any previous instrument, significant discoveries are bound to follow,” said SLAC astrophysicist Greg Madejski, who is leading the KIPAC contingent. Dr. Madejski was also part of the creative team that created NuSTAR's scientific parameters - both before the telescope was built and while it is in operation.
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“The most important study will involve the cosmic X-ray background -- understanding the individual phenomena that contribute to it,” Madejski said.
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<center><iframe width="560" height="315" src="http://www.youtube.com/embed/eU_x6EVXdoc?rel=0" frameborder="0" allowfullscreen></iframe></center>
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Just what will NuSTAR look at? Imagine scanning the event horizon of a black hole where particles are crammed together like soapsuds going down a drain. Or peering into a high energy Universe where jets of material spew from active galactic nuclei. NuSTAR will go beyond information sent back by telescopes like the Fermi Gamma-Ray Space Telescope. The gamma rays captured by Fermi don’t provide enough information to fully explain what powers these jets; according to Madejski, the hope is that NuSTAR will be able to measure the jets’ contents and reveal some of the high-energy processes that accelerate the contents to such great speeds.
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"NuSTAR can convert high-energy X-ray photons into sharp images because of its innovative telescope design." said SLAC engineering physicist Jason Koglin, who currently helps users of the Linac Coherent Light Source get the information they need from the LCLS X-rays. Previously, he was at Columbia University working with the team that developed NuSTAR’s mirrors. “The whole telescope is basically a set of nested reflective mirrors,” which are designed to deflect light onto the special solid-state detector, said Koglin. "Each of its two identical optics modules is made of 133 layers of concentric, cone-shaped shells, each shell built of between 12 and 24 individual segments, all molded from ultra-thin glass similar to what’s found in laptop screens and glazed with hundreds of layers of reflective coatings."
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Although this technology is cutting-edge, the advanced mirror design can on deflect X-rays to a small amount. Within a week of launch, a specialized lightweight gantry will be employed. This maneuver will increase the "space" between the modules and the main telescope by an additional 33 feet. This will enable the deflected X-rays to converge in a perfect position.
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Holding his breath, Koglin patiently waits with the other KIPAC scientists to decipher the messages that NuSTAR will deliver. “Multi-band studies are so important,” he said -- in other words, studying the same phenomenon in NuSTAR’s hard X-rays and Fermi’s gamma rays, or in the less energetic X-rays detected by the Chandra X-ray Telescope. “It’s like looking at different colors in a very broad spectrum,” he said. “If one of the colors isn’t there, you can’t even tell you’re missing something.”
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Thanks NuSTAR, the bare bones of the Cosmos will soon be ours to discover.
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<i>Contributed by Tammy Plotner. Original Story Source: <a href="http://news.stanford.edu/news/2012/june/nustar-slac-telescope-061412.html" target="blank">Stanford University News Release</a>.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-35103846929131717302012-06-18T10:51:00.001-07:002012-06-18T10:51:15.426-07:00Weekly SkyWatcher's Forecast: June 18-24, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/06/NGC-3981.gif"><img src="http://www.universetoday.com/wp-content/uploads/2012/06/NGC-3981-578x580.gif" alt="" width="578" height="580" class="size-medium wp-image-95872" /></a>
Greetings, fellow SkyWatchers! Let's begin the week with some awesome galactic studies and enjoy a meteor shower during Summer Solstice! We'll be studying variable stars, the planet Mars, Saturn, the Moon and Mercury, too! There's always a bit of astronomy history and some unusual things to learn about. When you're ready, just meet me in the back yard... <a name='more'></a>
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<b>Monday, June 18</b> – With dark skies on our side, we’ll spend the next few days concentrating on a very specific region of the night sky. Legend tells us the constellation of Crater is the cup of the gods – cup befitting the god of the skies, Apollo. Who holds this cup, dressed in black? It’s the Raven, Corvus. The tale is a sad one – a story of a creature sent to fetch water for his master, only to tarry too long waiting on a fig to ripen. When he realized his mistake, the sorry Raven returned to Apollo with his cup and brought along the serpent Hydra in his claws as well. Angry, Apollo tossed them into the sky for all eternity and it is in the south they stay until this day.
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For the next few days, it will be our pleasure to study the Cup and the Raven. The galaxies I have chosen are done particularly for those of us who still star hop. I will start with a “marker” star that should be easily visible unaided on a night capable of supporting this kind of study. The field stars are quite recognizable in the finder and this is an area that takes some work. Because these galaxies approach magnitude 13, they are best suited to the larger telescope.
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Now, let’s go between map and sky and identify both Zeta and Eta Crater and form a triangle. Our mark is directly south of Eta the same distance as between the two stars. At low power, the 12.7 magnitude NGC 3981 (Right Ascension: 11 : 56.1 - Declination: -19 : 54) sits inside a stretched triangle of stars. Upon magnification, an elongated, near edge-on spiral structure with a bright nucleus appears. Patience and aversion makes this “stand up” galaxy appear to have a vague fading at the frontiers with faint extensions. A moment of clarity is all it takes to see tiny star caught at the edge.
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<b>Tuesday, June 19</b> – New Moon! Tonight’s first study object, 12.7 magnitude NGC 3956 (Right Ascension: 11 : 54.0 - Declination: -20 : 34) is about a degree due south of NGC 3981. When first viewed, it appears as edge-on structure at low power. Upon study it takes on the form of a highly inclined spiral. A beautiful multiple star, and a difficult double star also resides with the NGC 3956 – appearing almost to triangulate with it. Aversion brings up a very bright core region which over the course of time and study appears to extend away from the center, giving this very sweet galaxy more structure than can be called from it with one observation.
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Our next target is a little more than two degrees further south of our last study. The 12.8 magnitude NGC 3955 (Right Ascension: 11 : 54.0 - Declination: -23 : 10) is a very even, elongated spiral structure requiring a minimum of aversion once the mind and eye “see” its position. Not particularly an impressive galaxy, the NGC 3955 does, however, have a star caught at the edge as well. After several viewings, the best structure I can pull from this one is a slight concentration toward the core.
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Now we’ll study an interacting pair and all that is required is that you find 31 Corvii, an unaided eye star west of Gamma and Epsilon Corvii. Now we’re ready to nudge the scope about one degree north. The 11th magnitude NGC 4038/39 (Right Ascension: 12 : 01.9 - Declination: -18 : 52) is a tight, but superior pair of interacting galaxies. Often referred to as either the “Ringtail” or the “Antenna”, this pair deeply captured the public’s imagination when photographed by the Hubble. (Unfortunately, we don’t have the Hubble, but what we have is set of optics and the patience to find them.) At low power the pair presents two very stellar core regions surrounded by a curiously shaped nebulosity. Now, drop the power on it and practice patience – because it’s worth it! When that perfect moment of clarity arrives, we have crackling structure. Unusual, clumpy, odd arms appear at strong aversion. Behind all this is a galactic “sheen” that hints at all the beauty seen in the Hubble photographs. It’s a tight little fellow, but worth every moment it takes to find it.
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Return to 31 Corvii and head one half degree northwest to discover 11.6 magnitude NGC 4027 (Right Ascension: 11 : 59.5 - Declination: -19 : 16). Relatively large, and faint at low power, this one also deserves both magnification and attention. Why? Because it rocks! It has a wonderful coma shape with a single, unmistakable bold arm. The bright nucleus seems to almost curl along with this arm shape and during aversion a single stellar point appears at its tip. This one is a real treat!
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<b>Wednesday, June 20</b> – Today marks the official date of 2012 Summer Solstice!
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With no Moon to contend with in the predawn hours, we welcome the “shooting stars” as we pass through another portion of the Ophiuchid meteor stream. The radiant for this pass will be nearer Sagittarius and the fall rate varies from 8 to 20, but it can sometimes produce unexpectedly more.
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Tonight let’s look to the sky again and fixate on Eta Crater – our study lay one half degree southeast. The 12.8 magnitude NGC 4033 (Right Ascension: 12 : 00.6 - Declination: -17 : 51) is a tough call even for a large scope. Appearing elliptical at low power, it does take on some stretch at magnification. It is smallish, even and quite unremarkable. It requires good aversion and a bit of patience to find. Good luck!
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The last of our studies resides by a star, one degree west of Beta Corvii. In order to “see” anything even remotely called structure in NGC 4462 (Right Ascension: 12 : 29.3 - Declination: -23 : 10), this one is a high power only galaxy that is best when the accompanying star is kept out of the field as much as possible. It holds a definite stellar nucleus and a concentration that pulls away from it making it almost appear barred. On an exceptional night with a large scope, wide aversion and moments of clarity show what may be three to four glints inside the structure. Ultra tiny pinholes in another universe? Or perhaps an unimaginably huge, bright globular clusters? While attention is focused on trying to draw out these points, you’ll notice this galaxy’s structure much more clearly. Another true beauty and fitting way to end this particular study field!
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<b>Thursday, June 21</b> – Keep an eye out for the exiting planet Mars! It’s been on the move and has now crossed the border of Virgo and returned to Leo. Have you noticed it quickly changing in both apparent brightness and size? It won’t be long until it’s gone! And speaking of planets on the move, have you spotted Mercury yet? You can find the swift little planet low on the western horizon just after sunset. Look for it just to the south of Castor and Pollux!
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For challenging larger telescope studies, return to eastern edge of Mare Crisium and Promontorium Agarum to identify shallow crater Condorcet to its east. Look along the shore of the mare for a mountain to the south known as Mons Usov. Just to its north Luna 24 landed and directly to its west are the remains of Luna 15. We'll study more about them in the future. Can you spot the tiny dark well of crater Fahrenheit nearby? Continue with your telescope north of Mare Crisium for even more challenging features such as northeast limb studies Mare Smythii and Mare Marginis. Between them you will see the long oval crater Jansky - bordered by Jansky A at the very outer edge.
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While you’re out tonight, take a look at the skies for a circlet of seven stars that reside about halfway between orange Arcturus and brilliant blue/white Vega. This quiet constellation is named Corona Borealis – or the “Northern Crown.” Just northwest of its brightest star is a huge concentration of over 400 galaxies that reside over a billion light-years away from us. This area is so small from our point of view that we could cover it with our thumbnail held at arm’s length!
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For variable star fans, let’s explore Corona Borealis and focus our attention on S – located just west of Theta – the westernmost star in the constellation’s arc formation. At magnitude 5.3, this long-term variable takes almost a year to go through its changes; usually far outshining the 7th magnitude star to its northeast – but will drop to a barely visible magnitude 14 at minimum. Compare it to the eclipsing binary U Coronae Borealis about a degree northwest. In slightly over three days this Algol-type will range by a full magnitude as its companions draw together.
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<b>Friday, June 22</b> – Today celebrates the founding of the Royal Greenwich Observatory in 1675. That’s 332 years of astronomy! Also on this date in history, in 1978, James Christy of the US Naval Observatory in Flagstaff Arizona discovered Pluto’s satellite Charon.
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If you’d like to practice some unaided eye astronomy, then look no further than the western skyline as the Sun sets. At twilight you’ll first notice the very slender crescent Moon – but don’t delay your observations as you can spot Mercury to the west! The inner planet will set very fast, so you’ll need an open horizon. But that’s not all… the speedy little dude is lined up perfectly with Castor and Pollux! With the foursome nearly “in a row” this will make a very cool apparition to remind friends and family to watch for!
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Now, grab your favorite optics for a selenographic treat tonight return to the area just north of Mare Crisium area to observe spectacular crater Cleomides. This two million year old crater is separated from Crisium by some 60 kilometers of mountainous terrain. Telescopically, Cleomides is a true delight at high power. To Cleomides' east, begin by identifying Delmotte, and to the northwest, Trailes and Debes. About twice Clemoides' width northwest, you will see a sharply well-defined Class I crater Geminus. Named for the Greek astronomer and mathematician Geminos, this 86 kilometer wide crater shows a smooth floor and displays a long, low dune across its middle.
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When you’re finished, point your binoculars or telescopes back towards Corona Borealis and about three fingerwidths northwest of Alpha for variable star R (Ra 15. 48.6 Dec +28 09). This star is a total enigma. Discovered in 1795, most of the time R carries a magnitude near 6, but can drop to magnitude 14 in a matter of weeks – only to unexpectedly brighten again! It is believed that R emits a carbon cloud which blocks its light. When studied at minima, the light curve resembles a “reverse nova,” and has a peculiar spectrum. It is very possible this ancient Population II star has used all of its hydrogen fuel and is now fusing helium to carbon. It’s so odd that science can’t even directly determine its distance!
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<b>Saturday, June 23</b> – If you missed yesterday’s apparition of Mercury, then try again tonight. While the small planet might be dim, just look for the brighter pairing of Castor and Pollux above the western horizon at twilight. Can’t find it? Then try this. When you look at this famous pair of stars, judge the distance between the two. Now, apply that same distance and angle to the left (southern) star, Pollux, and you’ve found Mercury! Need more? Then check out the Moon and you’ll see Regulus is about a fistwidth to the east/southeast and Mars is a little more than two handspans to the southeast. Still more? Then continue on from Mars southeast about about another two handspans and you’ll see the pairing of Spica and Saturn!
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Using your telescope tonight on the Moon will call up previous study craters, Atlas and Hercules to the lunar north. If you walk along the terminator to the due west of Atlas and Hercules, you'll see the punctuation of 40 kilometer wide Burg just emerging from the shadows. While it doesn't appear to be a grand crater just yet, it has a redeeming feature - it's deep - real deep. If Burg were filled with water here on Earth, it would require a deep submergence vehicle like ALVIN to reach its 3680 meter floor! This class II crater stands nearly alone on an expanse of lunarscape known as Lacus Mortis. If the terminator has advanced enough at your time of viewing, you may be able to see this walled-plain's western boundary peeking out of the shadows.
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While we’re out, let’s have a look at Delta Serpens. To the eye and binoculars, 4th magnitude Delta is a widely separated visual double star… But power up in the telescope to have a look at a wonderfully difficult binary. Divided by no more than 4 arc seconds, 210 light-year distant Delta and its 5th magnitude companion could be as old as 800 million years and on the verge of becoming evolved giants. Separated by about 9 times the distance of Pluto from our Sun, the white primary is a Delta Scuti-type variable which changes subtly in less than four hours. Although it takes the pair 3200 years to orbit each other, you’ll find Delta Serpens to be an excellent challenge for your optics.
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<b>Sunday, June 24</b> – On this day in 1881, Sir William Huggins made the first photographic spectrum of a comet (1881 III) and discovered cyanogen (CN) emission at violet wavelengths. Unfortunately, his discovery caused public panic around 29 years later when Earth passed through the tail of Halley’s Comet. What a shame the public didn’t realize that cyanogens are also released organically! More than fearing what is in a comet’s tail, they should have been thinking about what might happen should a comet strike. Tonight look at the wasted Southern Highland area of the Moon with new eyes… Many of these craters you see were caused by impacts – some as large as the nucleus of Halley itself.
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Now let's pick up a binocular curiosity located on the northeast shore of Mare Serenitatis. Re-identify the bright ring of Posidonius, which contains several equally bright points both around and within it - and look at Mare Crisium and get a feel for its size. A little more than one Crisium's length west of Posidonius you'll meet Aristotle and Eudoxus. Drop a similar length south and you will be at the tiny, bright crater Linne on the expanse of Mare Serenitatis. So what's so cool about this little white dot? With only binoculars you are resolving a crater that is one mile wide, in a seven mile wide patch of bright ejecta - from close to 400,000 kilometers away! While you were there, did you notice how much Proclus has changed tonight? It is now a bright circle and beginning to show bright lunar rays...
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Before we head for deep sky, be sure to at least take a look at Saturn and Mars. Right now the Ring King has reached its greatest westward position and will begin its tour back to the east. Now, check out Mars’ position to the west and measure with your hands roughly how far apart they are. At this point they are separated by about two handspans. Check again in a few weeks to see planetary motion displayed right before your eyes!
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Now let’s turn binoculars or telescopes towards magnitude 2.7 Alpha Librae – the second brightest star in the celestial “Scales.” Its proper name is Zuben El Genubi, and even as “Star Wars” as that sounds, the “Southern Claw” is actually quite close to home at a distance of only 65 light-years. No matter what size optics you are using, you’ll easily see Alpha’s 5th magnitude companion widely spaced and sharing the same proper motion. Alpha itself is a spectroscopic binary which was verified during an occultation event, and its inseparable companion is only a half magnitude dimmer according to the light curves. Enjoy this easy pair tonight!
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Until next week? Ask for the Moon... But keep on reaching for the stars!
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<i>Written by Tammy Plotner. NGC 3981 - Credit: Palomar Observatory, Courtesy of Caltech.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-60105888674537884212012-06-11T13:55:00.001-07:002012-06-11T13:55:55.655-07:00Weekly SkyWatcher's Forecast: June 11-17, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/06/m5y.jpg"><img src="http://www.universetoday.com/wp-content/uploads/2012/06/m5y-580x580.jpg" alt="" title="m5y" width="580" height="580" class="size-medium wp-image-95796" /></a>
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Greetings, fellow SkyWatchers! You can breathe now... the Venus Transit is over and we're back to the mundane astronomical excitement like great globular clusters, an early morning conjunction and two meteor showers - the Ophiuchids and June Lyrids. If you're up to the ordinary, then follow along as we capture some great galaxies and a very challenging study! Dust off your optics and meet me in the back yard... <a name='more'></a>
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<b>Monday, June 11</b> – Tonight we make the jump to Serpens Caput, which is in itself a challenge to recognize with the unaided eye. Using bright Spica as a guide, look about a handspan northeast for two of the brightest stars in the constellation – Alpha, and Lambda to its northeast. Using binoculars, locate a pairing with Delta to the north-northwest and Mu to the south. Now return to Alpha and hop a little less than a fistwidth to the southwest where you will encounter double star 5 Serpens and the mighty M5 (Right Ascension: 15 : 18.6 - Declination: +02 : 05).
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While Gottfried Kirch and his wife Maria were watching a comet on May 5, 1702, they stumbled across a huge, bright object that they considered a “nebulous star.” Forty-two years later, it was found again by Messier who labeled it as M5 and described it as a round nebula which didn’t contain any stars. But, thank heaven for William Herschel! Some 27 years later he counted up to 200 resolvable stars in this globular cluster and reported “the middle is so compressed that it is impossible to distinguish the components.”
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Even in today’s binoculars, M5 shows a grainy texture that begins resolution to even the smallest of telescopes and invites larger ones to an explosion of stellar population. Slightly elliptical in appearance, M5 is believed to be one of the oldest globular clusters with a calculated age of 13 billion years, and it contains 105 known variable stars – as well as a dwarf nova. At a distance of 24,500 light-years and stretching across 165 light-years of space, this magnificent object so dominates its territory that it would gather in any stars straying within 400 light-years of its tidal influence!
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Mid-to-larger telescopes will begin such awesome resolution on M5′s many chains and its bright core region that it will be a cluster you will visit again and again over the years. No matter what size binoculars or telescope you use, this 5.6 magnitude class V globular cluster is one of the five brightest of all!
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<b>Tuesday, June 12</b> – As with all astronomical projects, there are sometimes difficult ones needed to complete certain study fields – such as challenging globular clusters. Tonight we’ll take a look at one such cluster needed to complete your list and you’ll find it by using M5 as a guide.
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Palomar 5 is by no stretch of the imagination easy. For those using GoTo systems and large telescopes, aiming is easy… But for star hoppers a bit of instruction goes a long way. Starting at M5 drop south for the double 5 Serpens and again south and slightly west for another, fainter double. Don’t confuse it with 6 Serpens to the east. About half a degree west you’ll encounter an 8th magnitude star with 7th magnitude 4 Serpens a half degree south. Continue south another half degree where you will discover a triangle of 9th magnitude stars with a southern one at the apex. This is home to Palomar 5 (RA 15 16 05.30 Dec -00 06 41.0).
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Discovered by Walter Baade in 1950, this 11.7 magnitude, Class XII globular is anything but easy. At first it was believed to be a dwarf elliptical and possibly a member of our own Local Group of galaxies due to some resolution. Later studies showed that Palomar 5 was indeed a globular cluster – but one that was being ripped apart by the tidal forces of the Milky Way.
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75,000 light-years away from us and 60,000 light-years from the galactic center, Palomar 5′s members are escaping and leaving trails that span 13,000 light-years…a process which may have been happening for several billion years. Although it is of low surface brightness, even telescopes as small as 6″ can distinguish just a few individual members northwest of the 9th magnitude marker star – but even telescopes as large as 31″ fail to show much more than a faint sheen (under excellent conditions) with a handful of resolvable stars. Even though it may be one of the toughest you’ll ever tackle, be sure to take the time to make a quick sketch of the region to complete your studies. Good luck!
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<b>Wednesday, June 13</b> –Today in 1983, Pioneer 10 becomes the first manmade object to leave the solar system. What wonders would it see? Are there other galaxies out there like our own? Will there be life like ours? While we can’t see through Pioneer’s “eyes,” tonight let’s use our own as we quest for a look in the mirror…
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Our object will be Herschel II.76 – also known as NGC 5970. Begin by identifying Beta and Delta Serpens Caput and look for finderscope Chi between them. Less than a degree southwest you will see a similar magnitude double star. Hop about 1/3 degree northwest and you will find your galaxy mark just a fraction southwest of a 7th magnitude star (RA 15 38 30.12 Dec -12 11 10.9).
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NGC 5970 is not particularly easy for smaller scopes even near 11th magnitude because of low surface brightness, but it could be a distant twin of our own galaxy, so similar is it to the Milky Way in structure. At 105 million light-years away, it is no great surprise that we see it as faint – for its light left around the time the dinosaurs ruled the Earth. Stretching across 85,000 light-years of space, this grand spiral has been extensively studied in its nucleus region, obscuring dust regions, and stellar population. And – like us – it is also part of its own local group.
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While smaller telescopes will make out a slight elongated mist, in mid-to-large aperture NGC 5970 will appear oval shaped with a bright core and evidence of a central bar. While the edges of the galaxy seem well defined, look closely at the narrower ends where material seems more wispy. While averted in this fashion, the nucleus will sometimes take on a stellar appearance – yet lose this property with direct vision. Be sure to mark your Herschel notes on this one!
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<b>Thursday, June 14</b> – As the new hours of the day begin and you wait on dawn, keep watch for the peak of the Ophiuchids meteor shower with the radiant near Scorpius. The fall rate is poor with only 3 per hour, but fast moving bolides are common. This meteor stream will last for 25 days.
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Tonight, while we have plenty of dark skies to go around, let’s go south in Libra and have a look at the galaxy pairing NGC 5903 (Right Ascension: 15 : 18.6 - Declination: -24 : 04) and NGC 5898 (Right Ascension: 15 : 18.2 - Declination: -24 : 06). You’ll find them about three degrees northeast of Sigma, and just north of a pair of 7th magnitude stars.
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While northernmost NGC 5903 seems to be nothing more than a faint elliptical with a brighter concentration towards the center and an almost identical elliptical – NGC 5898 – to the southwest, you’re probably asking yourself… Why the big deal over two small ellipticals? First off, NGC 5903 is Herschel III.139 and NGC 5898 is Herschel III.138… two more to add to your studies. And second? The Very Large Array has studied this galaxy pair in the spectral lines of neutral hydrogen. The brighter of the pair, NGC 5898, shows evidence of ionized gas which has been collected from outside its galactic realm – while NGC 5903 seems to be running streamers of material towards it. A double-galaxy, double-accretion event!
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But there’s more…
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Look to the southeast and you’ll double your pleasure and double your fun as you discover two double stars instead of just one! Sometimes we overlook field stars for reasons of study – but don’t do it tonight. Even mid-sized telescopes can easily reveal this twin pair of galaxies sharing “their stuff,” as well as a pair of double stars in the same low power field of view. (Psst… slim and dim MCG 043607 and quasar 1514-241 are also here!) Ain’t it grand?
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<b>Friday, June 15</b> – Tonight, before you hunt down the faint fuzzies and spend the rest of the night drooling on the Milky Way, let’s go globular and hunt up two very nice studies worthy of your time. Starting at Alpha Librae, head five degrees southeast for Tau and yet another degree southeast for the splendid field of NGC 5897 (RA 15 17 24.40 Dec -21 00 36.4).
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This class XI globular might appear very faint to binoculars, but it definitely makes up for it in size and beauty of field. It was first viewed by William Herschel on April 25, 1784 and logged as H VI.8 – but with a less than perfect notation of position. When he reviewed it again on March 10, 1785 he logged it correctly and relabeled it as H VI.19. At a distance of a little more than 40,000 light-years away, this 8.5 magnitude globular will show some details to the larger telescope, but remain unresolved to smaller ones. As a halo globular cluster, NGC 5897 certainly shows signs of being disrupted and has a number of blue stragglers as well as four newly discovered variables of the RR Lyrae type.
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Now let’s return to Alpha Librae and head about a fistwidth south across the border into Hydra and two degrees east of star 57 for NGC 5694 – also in an attractive field (RA 14 39 36.52 Dec -26 32 18.0).
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Also discovered by Herschel, and cataloged as H II.196, this class VII cluster is far too faint for binoculars at magnitude 10, and barely within reach of smaller scopes. As one of the most remote globular clusters in our galaxy, few telescopes can hope to resolve this more than 113,000 light-year distant ball of stars whose brightest is magnitude 16.5 – and it also possesses no variables. Traveling at 190 kilometers per second, metal-poor NGC 5694 will not have the same fate as NGC 5897… For this is a globular cluster that is not being pulled apart by our galaxy – but escaping it!
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<b>Saturday, June 16</b> – No matter if you stayed up late chasing deep sky, or got up early, right now is the time to catch the peak of the June Lyrids meteor shower. Although it’s not the most outstanding of displays, no Moon will make it one of the best prospects of the year for those wishing to log their meteor observations. Look for the radiant near bright Vega – you may see up to 15 faint blue meteors per hour from this branch of the May Lyrid meteor stream.
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Today in 1963, Valentina Tereshkova, aboard the Soviet Vostok 6, became the first woman ever to go into space. Her solo flight is still unique. Twenty years later, on the 18th, Sally Ride became the first American woman in orbit, aboard the Space Shuttle.
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For observers of all skill levels and equipment, it’s simply time to stop and have a look at a seasonal favorite which is now nearly overhead – M13 (Right Ascension: 16 : 41.7 - Declination: +36 : 28). You’ll find this massive globular cluster quite easy to locate on the western side of the Hercules “keystone” about 1/3 the way between the northern and southern stars – Eta and Zeta.
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At a little brighter than magnitude 6, this 25,100 light-year distant globular cluster can be seen unaided from a dark sky location. First noted by Edmond Halley in 1714, the “Great Hercules Cluster” was cataloged by Messier on June 1, 1764. Filled with hundreds of thousands of stars, yet only one young blue star, M13 could be as much as 14 billion years old.
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Thirty-three years ago, the Great Hercules Cluster was chosen by the Arecibo Observatory as the target for the first radio message delivered into space, yet it will be a message that won’t be received for over 25 centuries. Look at it with wonder tonight… For the light that left as you are viewing it tonight did so at a time when the Earth was coming out of the Ice Age. Our early ancestors were living in caves and learning to use rudimentary tools. How evolved would our civilization be if we ever received an answer to our call?!
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<b>Sunday, June 17</b> – Celestial scenery alert! If you’re up before the Sun rises, be sure to check out the eastern skyline for the very close apparition of the Moon and Jupiter. The two will only be separated by about a half a degree. What a great way to wake up!
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As the sky darkens tonight, let’s discover the wonderful world of low power. Start your journey by re-locating magnificent M13 and move about 3 degrees northwest. What you will find is a splendid loose open cluster of stars known as Dolidze/Dzimselejsvili (DoDz) 5 – and it looks much like a miniature of the constellation of Hercules. Just slightly more than 4 degrees to its east and just about a degree south of Eta Hercules is DoDz 6, which contains a perfect diamond pattern and an asterism of brighter stars which resembles the constellation of Sagitta.
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Now we’re going to move across the constellation of Hercules towards Lyra. East of the “keystone” you will see a tight configuration of three stars – Omicron, Nu and Xi. About the same distance that separates these stars to the northeast you will find DoDz 9. Using minimal magnification, you’ll see a pretty open cluster of around two dozen mixed magnitude stars that are quite attractive. Now look again at the “keystone” and identify Lambda and Delta to its south. About midway between them and slightly to the southeast you will discover the stellar field of DoDz 8. The last is easy – all you need to do is know the beautiful red/green double, Ras Algethi (Alpha). Move about 1 degree to the northwest to discover the star-studded open cluster DoDz 7. These great open clusters are very much off the beaten path and will add a new dimension to your large binocular or low power telescoping experiences.
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Until next week, keep your eyes on the skies!
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<i>Written by Tammy Plotner. Messier 5 - Credit: Hillary Mathis, REU Program/NOAO/AURA/NSF</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-19560015033922458942012-06-03T14:59:00.000-07:002012-06-03T15:06:57.641-07:00Weekly SkyWatcher's Forecast: June 4-10, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/06/strawberry.jpg"><img src="http://www.universetoday.com/wp-content/uploads/2012/06/strawberry-580x565.jpg" title="strawberry" width="580" height="565" class="size-medium wp-image-95611" /></a>
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Greeting, fellow SkyWatchers! It's gonna' be a great week! We start off with a partial lunar eclipse of the Strawberry Moon, head into the historic Venus Transit, study some Herschel objects, catch both the Scorpid and Arietid Meteor Showers, practice some binocular astronomy and even take on some challenge objects! How awesome is that? Whenever you're ready, just follow me into the back yard... <a name='more'></a>
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<b>Monday, June 4</b> – Tonight the Moon is full. Often referred to as the Full Strawberry Moon, this name was a constant to every Algonquin tribe in North America. But, our friends in Europe referred to it as the Rose Moon. The North American version came about because the short season for harvesting strawberries comes each year during the month of June – so the full Moon that occurs during that month was named for this tasty red fruit!
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This evening as the Sun sets and the Moon rises opposite of it, take advantage of some quiet time and really stop to look at the eastern horizon. If you are lucky enough to have clear skies, you will see the Earth’s shadow rising – like a dark, sometimes blue band – that stretches around 180 degrees of horizon. Look just above it for a Rayleigh scattering effect known as the “Belt of Venus”. This beautiful pinkish glow is caused by the backscattering of sunlight and is often referred to as the anti-twilight arch. As the Sun continues to set, this boundary between our shadow and the arch rises higher in the sky and gently blends with the coming night. What you are seeing is the shadow of the Earth’s translucent atmosphere, casting a shadow back upon itself. This happens every night! Pretty cool, huh?
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For some of us, it’s eclipse time! According to NASA’s Fred Espenak, most of the Americas will experience moonset before the partial lunar eclipse ends while eastern Asia will miss the beginning of the eclipse because it occurs before moonrise. The Moon's contact times with Earth's shadows are: Penumbral Eclipse Begins: 08:48:09 UT, Partial Eclipse Begins: 09:59:53 UT, Greatest Eclipse: 11:03:13 UT, Partial Eclipse Ends: 12:06:30 UT, Penumbral Eclipse Ends: 13:18:17. At the instant of greatest eclipse the umbral eclipse magnitude will reach 0.3705. At that time the Moon will be at the zenith for observers in the South Pacific. In spite of the fact that just a third of the Moon enters the umbral shadow (the Moon's southern limb dips 12.3 arc-minutes into the umbra) the partial phase still lasts over 2 hours. Be sure to visit the resource pages for a visibility map and links to precise times and locations!
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<b>Tuesday, June 5</b> - Heads up for all observers! Today’s universal date marks an historic event – Venus will transit the Sun! This event will cross international date lines, so be sure to know ahead of time when and where to watch. North America will be able to see the start of the transit, while South Asia, the Middle East, and most of Europe will catch the end of it. For some great information on when, where and how to watch, visit <a href="http://www.transitofvenus.org" target="blank">www.transitofvenus.org</a>. If you're clouded out, there's plenty of resources on-line to view this rare event. One that promises to have plenty of extra bandwidth to serve visitors is <a href="http://astronomylive.com/" target="blank">Astronomy Live</a>. Be there!!
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For all you Stargazers, keep watch for the Scorpid meteor shower. Its radiant will be near the constellation of Ophiuchus, and the average fall rate will be about 20 per hour with some fireballs.
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While you’re out, take the time to check out Alpha Herculis -Ras Algethi. You will find it not only to be an interesting variable, but a colorful double as well. The primary star is one of the largest known red giants and at about 430 light years away, it is also one of the coolest. Its 5.4 magnitude greenish companion star is easily separated in even small scopes – but even it is a binary! This entire star system is enclosed in an expanding gaseous shell that originates from the evolving red giant. Enjoy it tonight.
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<b>Wednesday, June 6</b> – So far we’ve studied many Herschel objects in disguise as Messier catalog items – but we haven’t really focused on some mighty fine galaxies that are within the power of the intermediate to large telescope. Tonight let’s take a serious skywalk as we head to 6 Comae and drop two degrees south.
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At magnitude 10.9, Herschel catalog object H I.35 is also known by its New General Catalog number of 4216 (Right Ascension: 12 : 15.9 - Declination: +13 : 09). This splendid edge-on galaxy has a bright nucleus and will walk right out in larger telescopes with no aversion required. But, the most fascinating part about studying anything in the Virgo cluster is about to be revealed.
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While studying structure in NGC 4216, averted vision picks up magnitude 12 NGC 4206 (Right Ascension:12 : 15.3 - Declination: +13 : 02) to the south. This is also a Herschel object – H II.135. While it is smaller and fainter, the nucleus will be the first thing to catch your attention – and then you’ll notice it is also an edge-on galaxy! As if this weren’t distracting enough, while re-centering NGC 4216, sometimes the movement is just enough to allow the viewer to catch yet another edge-on galaxy to the north – NGC 4222 (Right Ascension: 12 : 16.4 - Declination: +13 : 19). At magnitude 14, you can only expect to be able to see it in larger scopes, but what a treat this trio is!
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Is there a connection between certain types of galaxy structures within the Virgo cluster? Science certainly seems to think so. While low metallicity studies involving these galaxies are going on, research into evolution of galaxy clusters themselves continue to make new strides forward in our understanding of the universe. Capture them tonight!
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<b>Thursday, June 7</b> – If you’re up before dawn the next two days or out just after sunset, enjoy the peak of the June Arietid meteors – the year’s strongest daylight shower – with up to 30 visible per hour.
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If you’d like to try your ear at radio astronomy with the offspring of sungrazing asteroid Icarus, tune an FM radio to the lowest frequency not receiving a clear signal. An outdoor antenna pointed at the zenith increases your chances, but even a car radio can pick up strong bursts! Simply turn up the static and listen. Those hums, whistles, beeps, bongs, and occasional snatches of signals are our own radio signals being reflected off the meteor’s ion trail!
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Tonight let’s study a radio-source galaxy so bright it can be seen in binoculars – 8.6 magnitude M87 (Right Ascension: 12 : 30.8 - Declination: +12 : 24), about two fingerwidths northwest of Rho Virginis. This giant elliptical was discovered by Charles Messier in 1781 and cataloged as M87. Spanning 120,000 light-years, it’s an incredibly luminous galaxy containing far more mass and stars than the Milky Way – gravitationally distorting its four dwarf satellites galaxies. M87 is known to contain in excess of several thousand globular clusters – up to 150,000 – and far more than our own 200.
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In 1918, H. D. Curtis of Lick Observatory discovered something else – M87 has a jet of gaseous material extending from its core and pushing out several thousand light-years into space. This highly perturbed jet exhibits the same polarization as synchrotron radiation – a property of neutron stars. Containing a series of small knots and clouds as observed by Halton Arp at Palomar in 1977, he also discovered a second jet in 1966 erupting in the opposite direction. Thanks to these two properties, M87 made Arp’s “Catalog of Peculiar Galaxies” as number 152.
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In 1954 Walter Baade and R. Minkowski identified M87 with radio source Virgo A, discovering a weaker halo in 1956. Its position over an x-ray cloud extending through the Virgo cluster make M87 a source of an incredible amount of x-rays. Because of its many strange properties, M87 remains a target of scientific investigation. The Hubble has shown a violent nucleus surrounded by a fast rotating accretion disc, whose gaseous make-up may be part of a huge system of interstellar matter. As of today, only one supernova event has been recorded – yet M87 remains one of the most active and highly prized study galaxies of all. Capture it tonight!
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<b>Friday, June 8</b> – Born on this date in 1625 was Giovanni Cassini – the most notable observer following Galileo. As head of the Paris Observatory for many years, he was the first to observe seasonal changes on Mars and measure its parallax (and so, its distance). This set the scale of the solar system for the first time. Cassini was the first to describe Jovian features, and studied the Galilean moons’ orbits. He also discovered four moons of Saturn, but he is best remembered for being the first to see the namesake division between the A and B rings.
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Why not honor Cassini’s work by visiting Saturn tonight? In case you hadn’t noticed, the beautiful yellowish “star” has been on the move and is now around a degree away to the southeast from a previous study star – Porrima! Not only is this a lovely visual, but an easy way to find Saturn if you’re new to the game. Seeing the Cassini Division in Saturn’s ring structure and some of the smaller moons will require at least a 114mm telescope and steady seeing. Use as much magnification as conditions will allow and look for unusual things – like seeing the planet edge through the gap!
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Tonight we’ll use Rho Virginis as a stepping stone to more galaxies. Get on your mark and move one and a half degrees north for M59 (Right Ascension:12 : 42.0 - Declination: +11 : 39)…
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First discovered in 1779 by J. G. Koehler while studying a comet, this 11th magnitude elliptical galaxy was observed and labeled by Messier who was just a bit behind him. Much denser than our own galaxy, M59 is only about one-fourth the size of the Milky Way. In a smaller telescope, it will appear as a faint oval, while larger telescopes will make out a more concentrated core region.
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Now shift one half degree east for brighter and larger M60. Also caught first by Koehler on the same night as M59, it was “discovered” a day later by yet another astronomer who had missed M59! It took Charles Messier another four days until this 10th magnitude galaxy interfered with his comet studies and was cataloged. At around 60 million light-years away, M59 is one of the largest ellipticals known and has five times more mass than our galaxy. As a study object of the Hubble Telescope, this giant has shown a concentrated core with over 2 billion solar masses. Photographed and studied by large terrestrial telescopes, M59 may contain as many as 5100 globular clusters in its halo.
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While our backyard equipment is essentially revealing M59′s core, there is a curiosity here. It shares “space” with spiral galaxy NGC 4647 (Right Ascension: 12 : 43.5 - Declination: +11 : 35). Telescopes of even modest aperture will pick up the nucleus and faint structure of this small face-on galaxy. Harlow Shapely found the pair odd because – while they are relatively close in astronomical terms – they are very different in age and development. Halton Arp also studied this combination of an elliptical galaxy affecting a spiral and cataloged it as “Peculiar Galaxy 116.” Be sure to mark your notes!
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<b>Saturday, June 9</b> – Today is the birthday of Johann Gottfried Galle. Born in Germany in 1812, Galle was the first observer to locate Neptune. He is also known for being Encke’s assistant – and he’s one of the few astronomers ever to have observed Halley’s Comet twice. Unfortunately, he died two months after the comet passed perihelion in 1910, but at a ripe old age of 98! I wonder if he knew Mark Twain?
Tonight while we’re out, let’s have a look at a Virgo galaxy bright enough for smaller instruments and detailed enough to delight larger scopes. Starting at Delta Virginis, move about a fistwidth to the west where you will see two fainter stars, 16 (south) and 17 (north) Virginis. You’ll find M61 (Right Ascension:12 : 21.9 - Declination: +04 : 28) located about one-half degree south of the yellow double star 17.
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Its discovery was credited to Barnabus Oriani during that fateful year of 1779 when Messier was so avid about chasing a comet that he mistook it for one. While Charles had seen it on the same night, it took him two days to figure out it wasn’t moving and four more before he cataloged it. Fortunately, 7 years later Mr. Herschel assigned it his own number of H I.139, even though he wasn’t fond of assigning his own number to Messier catalog objects.
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At near 10th magnitude, this spiral galaxy will show a slightly elongated form and brighter core area to small telescopes, and really come to life in larger ones. Close to our own Milky Way galaxy in size, this larger member of the Virgo cluster has great spiral arm structure that displays both knots and dark dustlanes – as well as a beautifully developed nucleus region. M61 has also been host to four supernova events between 1926 and 1999 – all of which have been well within range of amateur telescopes.
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For an added Herschel treat tonight for larger scopes, hop back to star 17 and head about one half degree due west for near galactic pair NGC 4281 (H II.573) and NGC 4273 (H II.569). Here is a study of two galaxies similar in magnitude (12) and size – but of different structure. Northeastern NGC 4281 (Right Ascension: 12 : 20.4 - Declination: +05 : 23) is an elliptical, and by virtue of its central concentration will appear slightly larger and brighter – while southwestern NGC 4273 (Right Ascension: 12 : 19.9 - Declination: +05 : 21) is an irregular spiral which will appear brighter in the middle but more elongated and faded along its frontiers. Sharp-eyed observers may also note fainter (13th magnitude) NGC 4270 (Right Ascension: 12 : 19.8 - Declination: +05 : 28) north of this pairing.
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Now, go back to Rho once again and about a fingerwidth northwest for yet another bright galaxy – M58 – a spiral galaxy actually discovered by Messier in 1779! As one of the brightest galaxies in the Virgo cluster, M58 (Right Ascension: 12 : 37.7 - Declination: +11 : 49) is one of only four that have barred structure. It was cataloged by Lord Rosse as a spiral in 1850. In binoculars, it will look much like our previously studied ellipticals, but a small telescope under good conditions will pick up the bright nucleus and a faint halo of structure – while larger ones will see the central concentration of the bar across the core. Chalk up another Messier study for both binoculars and telescopes and let’s get on to something really cool!
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Around a half degree southwest are NGC 4567 (Right Ascension: 12 : 36.5 - Declination: +11 : 15) and NGC 4569 (Right Ascension: 12 : 36.8 - Declination: +13 : 10). L. S. Copeland dubbed them the “Siamese Twins,” but this galaxy pair is also considered part of the Virgo cluster. While seen from our viewpoint as touching galaxies, no evidence exists of tidal filaments or distortions in structure, making them a line of sight phenomenon and not interacting members. While that might take little of the excitement away from the “Twins,” a supernova event has been spotted in NGC 4569 as recently as 2004. While the duo is visible in smaller scopes as two, with soft twin nuclei, intermediate and larger scopes will see an almost V-shaped or heart-shaped pattern where the structures overlap. If you’re doing double galaxy studies, this is a fine, bright one! If you see a faint galaxy in the field as well, be sure to add NGC 4564 (Right Ascension: 12 : 36.4 - Declination: +11 : 26) to your notes.
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<b>Sunday, June 10</b> – While I’m sure that unaided eye viewers and binocular users are tired of the galaxy hunt, be sure to take the time to look at many old favorites that are now in view. To the eye, one of the most splendid signs of the changing seasons is the Ursa Major Moving Group which sits above Polaris for northern hemisphere observers. For the southern hemisphere, the return of Crux serves the same purpose.
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Old favorites have now begun to appear again, such as Hercules, Cygnus and Scorpius… and with them a wealth of starry clusters and nebulae that will soon come into view as the night deepens and the hour grows late. Before we leave Virgo for the year, there is one last object that is seldom explored and such a worthy target that we must visit it before we go. Its name is NGC 5634 and you’ll find it halfway between Iota and Mu Virginis (RA 14 29.37 Dec -05 58.35)…First discovered by Sir William Herschel on March 5, 1785 and cataloged as H I.70, this magnitude 9.5 small globular cluster isn’t for everyone, but thanks to an 11th magnitude line-of-sight star on its eastern edge, it sure is interesting. At class IV, it’s more concentrated than many globular clusters, although its 19th magnitude members make it near impossible to resolve with backyard equipment.
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Located a bit more than 82,000 light-years from our solar system and about 69,000 light-years from the galactic center, you’ll truly enjoy this globular for the randomly scattered stellar field which accompanies it. In the finderscope, an 8th magnitude star will lead the way – not truly a member of the cluster, but one that lies between us. Capturable in scopes as small as 4.5″, look for a concentrated central area surrounded by a haze of stellar members – a huge number of which are recently discovered variables. While you look at this globular, keep this in mind… Based on observations with the Italian Telescopio Nazionale Galileo, it is now surmised that the NGC 5634 globular cluster has the same position and radial velocity as does the Sagittarius dwarf spheroidal galaxy. Because of the dwarf galaxy’s metal-poor population of stars, it is believed that NGC 5634 may have once been part of the dwarf galaxy – and been pulled away by our own tidal field to become part of the Sagittarius stream!
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Until next week? Wishing you clear skies for the Partial Lunar Eclipse, Venus Transit and the meteor showers!
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<i>Written by Tammy Plotner. Graphic Courtesy of Dave Reneke.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-45863903311943569042012-05-30T16:32:00.000-07:002012-05-30T16:32:31.907-07:00Trees Talk To Satellites<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQjIk3NMMenMbxZe2s-HDKYj70ZuIT0rLSVp9VXbmIaisLun4plh-h26pOiJMHjy5Zv4zMjOw2hLYTVXbwtI8hCV-WQhyZP3m69alP0TjSfuzjFz6c7Ld0dBl2BlSLDEK6CrrFed1GA-fe/s1600/trees.JPG" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="173" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQjIk3NMMenMbxZe2s-HDKYj70ZuIT0rLSVp9VXbmIaisLun4plh-h26pOiJMHjy5Zv4zMjOw2hLYTVXbwtI8hCV-WQhyZP3m69alP0TjSfuzjFz6c7Ld0dBl2BlSLDEK6CrrFed1GA-fe/s400/trees.JPG" /></a></div>
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If no one is in the forest, can you hear a tree fall? The answer is yes. Thanks to satellite communications, the forest industry is taking a whole new stand on how it harvests trees. Currently in the testing phase, this new method from the ESA combines satcoms and cellular services to relay important information almost immediately so less trees are used to produce a higher rate of timber. Timber? Timber! <a name='more'></a>
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The new system is called Satmodo and it was developed by an Irish company - Treemetrics. Working in cooperation with ESA, the communications line is now open between harvesting machines and their operators. Managers are now able to link to the computers inside the harvest vehicles via satellite and relay their instructions on how to cut and select trees to optimize their uses.
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Why is it important to communicate as to what trees are cut and when? When it comes to trees - not all a created equal. Some trees are better used to create pulp - the stuff of paper - while others are best utilized as sawlogs. This type of timber is delivered to the sawmill and is far more valuable. What sets it apart? Sawlog trees have a larger diameter and less knots in their structure. Accidentally harvesting sawlogs for pulp results in wasting precious resources and reduces crop value.
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Treemetrics is on the job. By employing 3D laser scanners to assist in measuring size, shape and straightness of standing trees, they are able to assess the value of a timber crop before harvesting. When an order is received, the information is turned into a "cut instruction" file which is relayed to the machine. This tells the operator how to harvest a select stand of trees in the forest. Until now, this information could only be sent via email, phone, or through verbal instructions. The process wasn't always an easy one. Information sent through email required manual entry into the vehicle's control computer and had to be uploaded each time a new file was needed.
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Now, thanks to satcoms, ESA provides the missing link in the chain - Satmodo’s two-way realtime or near-realtime connection with the harvesting machines. There is no more waiting until the forest has been clear cut. By collecting the information on timber yield per hectare and passing the information back through Satmodo, the cutting instructions can take place on the spot - or be changed as needed. This keeps workers constantly informed in areas where terrestrially-based mobile communications just won't work. What's more, Satmodo also acts as a "safety net" for remote locations.
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Consisting of a hybrid satellite/terrestrial wireless device, Satmodo is able to transmit data in real time via the new Inmarsat IsatM2M service. This is a two-way messaging route that not only empowers machine-to-machine tracking, but links them altogether - no matter how remote. This will create a fully integrated forestry management system connected together via satellite communications. Current plans for the Satmodo system includes installation into twenty harvesting machines.
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Timber? Timber!
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<i>Reported by Tammy Plotner. Original Story Source: <a href="http://www.esa.int/esaCP/SEM0UFGY50H_index_0.html" target="blank">ESA News Release</a> Image Credit: ESA.</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-11024862387414202972012-05-29T14:34:00.000-07:002012-05-29T14:36:25.501-07:00Weekly SkyWatcher's Forecast: May 28 - June 3, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/05/hadley_rima_damien_peach.jpg"><img src="http://www.universetoday.com/wp-content/uploads/2012/05/hadley_rima_damien_peach-580x475.jpg" alt="" title="hadley_rima_damien_peach" width="580" height="475" class="size-medium wp-image-95497" /></a>
<center><h6>Hadley Rille - Credit: Damian Peach</h6></center>
Greetings, fellow SkyWatchers! As the Venus Transit draws closer, our bright neighboring planet is quickly disappearing into the sunset glow. As we await this astronomical piece of history, let's take the time this week to have a look at a host of wonderful lunar features and bright stars. Be sure to catch the conjunction of Spica, Saturn and the Moon - and to catch a shooting star from the Tau Herculid meteor shower! If you're ready to learn more about the history, mystery and magic of astronomy, then grab your optics and meet me in the back yard... <a name='more'></a>
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<b>Monday, May 28</b> – On this day in 1959, the first primates made it to space. Abel (a rhesus monkey) and Baker (a squirrel monkey) lifted off in the nose cone of an Army Jupiter missile and were carried to sub-orbital flight. Recovered unharmed, Abel died just three days later from anesthesia during an electrode removal, but Baker lived on to a ripe old age of 27.
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Our first challenge for the evening will be a telescopic one on the lunar surface known as the Hadley Rille. Using our past knowledge of Mare Serenitatis, look for the break along its western shoreline that divides the Caucasus and Apennine mountain ranges. Just south of this break is the bright peak of Mons Hadley. You’ll find this area of highest interest for several reasons, so power up as much as possible.
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Impressive Mons Hadley measures about 24 by 48 kilometers at its base and reaches up an incredible 4572 meters. If this mountain was indeed caused by volcanic activity on the lunar surface, this would make it comparable to some of the very highest volcanically caused peaks on Earth, such as Mount Shasta or Mount Rainer. To its south is the secondary peak Mons Hadley Delta – the home of the Apollo 15 landing site just a breath north of where it extends into the cove created by Palus Putredinus.
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Along this ridgeline and smooth floor, look for a major fault line known as the Hadley Rille, winding its way across 120 kilometers of lunar surface. In places, the rille spans 1500 meters in width and drops to a depth of 300 meters below the surface. Believed to have been formed by volcanic activity some 3.3 billion years ago, we can see the impact that lower gravity has had on this type of formation, since earthly lava channels are less than 10 kilometers long and only around 100 meters wide.
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During the Apollo 15 mission, Hadley Rille was visited at a point where it was only 1.6 kilometers wide – still a considerable distance as seen in respect to astronaut James Irwin and the lunar rover. Over a period of time, its lava may have continued to flow through this area, yet it remains forever buried beneath years of regolith.
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Now let’s head about four fingerwidths northwest of Beta Virginis for another unusual star – Omega. Classed as an M-type red giant, this 480 light-year distant beauty is also an irregular variable which fluxes by about half a magnitude. Although you won’t notice much change in this 5th magnitude star, it has a very pretty red coloration and is worth the time to view.
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<b>Tuesday, May 29</b> – Today in 1919, a total eclipse of the Sun occurred and stellar measurements taken along the limb agreed with predictions based on Einstein’s General Relativity theory – the first such confirmation. Although we call it gravity, space/time curvature deflects the light of stars near the limb, causing their apparent positions to differ slightly. Unlike today’s astronomy, at that time you could only observe stars near the Sun’s limb (within less than an arc second) during an eclipse. It’s interesting to note that even Newton had his own theories on light and gravitation which predicted some deflection!
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Tonight on the Moon we’ll be looking for another challenging feature and a crater which conjoins it – Stofler and Faraday.
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Located along the terminator to the south, crater Stofler was named for Dutch mathematician and astronomer Johan Stofler. Consuming lunar landscape with an immense diameter of 126 kilometers and dropping 2760 meters below the surface, Stofler is a wonderland of small details in an eroded surrounding. Breaking its wall on the north is Fernelius, but sharing the southeast boundary is Faraday. Named for English physicist and chemist Michael Faraday, it is more complex and deeper at 4090 meters, but far smaller at 70 kilometers in diameter. Look for myriad smaller strikes which bind the two together!
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If you’re up for a bit more of a challenge, then let’s head about 59 light-years away in Virgo for star 70. You’ll find it located about 6 degrees northeast of Eta and right in the corner of the Coma, Bootes, and Virgo border. So what’s so special about this G-type, very normal-looking 5th magnitude star?
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It’s a star that has a planet.
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Long believed to be a spectroscopic binary because of its 117 day shifts in color, closer inspection has revealed that 70 Virginis actually has a companion planet. Roughly 7 times larger than Jupiter and orbiting no further away than Mercury from its cooler-than-Sol parent star, 70 Virginis B just might well be a planet cool enough to support water in its liquid form.
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How “cool” is that? Try about 85 degrees Celsius…
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<b>Wednesday, May 30 </b>– Are you ready to explore some more history? Then tonight have a look at the Moon and identify Alphonsus – it’s the centermost in a line of rings which looks much like the Theophilus, Cyrillus and Catharina trio.
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Alphonsus is a very old, Class V crater which spans 118 kilometers in diameter and drops below the surface by about 2730 meters and contains a small central peak. Partially flooded, Eugene Shoemaker had made of study of this crater’s formation and found dark haloes on the floor. Again, this could be attributed to volcanism and Shoemaker believed them to be maar volcanoes, and the haloes to be dark ash. Power up and look closely at the central peak, for not only did Ranger 9 hard land just northeast, but this is the only area on the Moon where an astronomer has observed a change and back up that observation with photographic proof.
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On November 2, 1958 Nikolai Kozyrev’s long and arduous study of Alphonsus was about to be rewarded. Some two years earlier Dinsmore Alter had taken a series of photographs from the Mt. Wilson 60″ reflector that showed hazy patches in this area that could not be accounted for. Night after night, Kozyrev continued to study at the Crimean Observatory – but with no success. During the process of guiding the scope for a spectrogram the unbelievable happened – a cloud of gas containing carbon molecules had been captured! Selected as the last target for the Ranger photographic mission series, Alphonsus delivered 5814 spectacular high-resolution images of this mysterious region before Ranger 9 splattered nearby.
Capture it yourself tonight!
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Now let’s add to our double star list as we hunt down Zeta Bootes located about 7 degrees southeast of Arcturus. This is a delightful multiple star system for even small telescopes.
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<b>Thursday, May 31</b> – As we begin the evening, be sure to note a splendid conjunction. Tonight the waxing Moon will dominate the sky, but it’s joined by the visage of Spica and Saturn. Look for the brilliant star located just to the lunar north and the gentle giant planet about 10 degrees or so further north.
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Now, let’s have a look at awesome crater Clavius. As a huge mountain-walled plain, Clavius will appear near the terminator tonight in the lunar southern hemisphere, rivaled only in sheer size by similar structured Deslandres and Baily. Rising 1646 meters above the surface, the interior wall slopes gently downward for a distance of almost 24 km and a span of 225 km. Its crater-strewn walls are over 56 km thick!
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Clavius is punctuated by many pockmarks and craters; the largest on the southeast wall is named Rutherford. Its twin, Porter, lies to the northeast. Long noted as a test of optics, Clavius crater can offer up to thirteen such small craters on a steady night at high power. How many can you see?
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While the glare will make it difficult to do many things, we can still have a look at other bright objects! Let’s start tonight by going just north of Zeta Bootes for Pi. With a wider separation, this pair of whites will easily resolve to the smaller telescope.
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Now skip up northeast about a degree for Omicron Bootes. While this is not a multiple system, it makes for a nice visual pairing for a binocular challenge. For telescopes, the southeastern star holds interest as a small asterism. Continue northeast another two degrees to discover Xi Bootes. This one is a genuine multiple star system with magnitude 5 and 7 companions. Not only will you enjoy this G-type sun for its duplicity, but for the fine field of stars in which it resides!
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Now have a look at Mars. Over the last few weeks it has dropped significantly in brightness and has now reached an approximate +0.5 magnitude. Have you been watching its progress against the background stars? It won’t be long until it crosses constellation boundaries again.
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<b>Friday, June 1</b> – Tonight on the Moon, crater Copernicus will try to steal the scene, head further south to capture another lunar club challenge – Bullialdus. Even binoculars can make out this crater with ease near the center of Mare Nubium. If you’re scoping – power up – this one is fun! Very similar to Copernicus, note Bullialdus’ thick, terraced walls and central peak. If you examine the area around it carefully, you can note it is a much newer crater than shallow Lubiniezsky to its north and almost non-existent Kies to the south. On Bullialdus’ southern flank, it’s easy to make out its A and B craters, as well as the interesting little Koenig to the southwest.
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Now let’s have a look at a tasty red star – R Hydrae. You’ll find it about a fistwidth south of Spica or about a fingerwidth west of Gamma Hydrae.
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R was the third long term variable star to be discovered and it is credited to Maraldi in 1704. While it had been observed by Hevelius some 42 years earlier, it was not recognized immediately because its changes happen over more than a year. At maximum, R reaches near 4th magnitude – but drops well below human eye perception to magnitude 10. During Maraldi’s and Hevelius’ time, this incredible star took over 500 days to change, but it has speeded up to around 390 days in the present century.
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Why such a wide range? Science isn’t really sure. R Hydrae is a pulsing M-type giant whose evolution may be progressing more rapidly than expected due to changes in structure. What we do know is that it is around 325 light-years away and is approaching us at around 10 kilometers per second.
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In the telescope, R will have a pronounced red coloration which deepens near minima. Nearby is 12th magnitude visual companion star Ho 381, which was first measured for position angle and distance in 1891. Since that time no changes in separation have been noted, which leads us to believe that the pair may be a true binary.
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<b>Saturday, June 2</b> – Tonight would be a wonderful opportunity for Moongazers to return to the surface and have a look at the peaceful Sinus Iridum area. If you’ve been clouded out before, be sure to have a look for telescopic lunar club challenges – Promontoriums Heraclides and LaPlace.
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Now let’s return again to R Hydrae. While observing a variable star with either the unaided eye, binoculars, or a telescope can be very rewarding, it’s often quite difficult to catch changes in long-term variables, because there are times when the constellation is not visible. While R Hydrae is unique in color, let’s drop about half a degree to the southeast to visit another variable star – SS Hydrae.
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SS is a quick change artist – the Algol-type. While you will need binoculars or a telescope to see this normally 7.7 magnitude star, at least its fluctuations are far more rapid, with a period of only 8.2 days. With R Hydrae we have a star that expands and contracts causing the changes in brightness – but SS is an eclipsing binary. While less than a half magnitude is not a noteworthy amount, you will notice a difference if you view it over a period of time. Be sure to note that this is actually a triple star system, for there is also a 13th magnitude companion star located 13″ from the primary. Watch if as often as possible and see if you can detect changes in the next few weeks!
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<b>Sunday, June 3</b> – If you’re up early, why not keep a watch out for the peak of the Tau Herculids meteor shower? These are the offspring of comet Schwassman-Wachmann 3, which broke up in 2006. The radiant is near Corona Borealis and we’ll be in this stream for about a month. At best when the parent comet has passed perihelion, you’ll catch about 15 per hour maximum. Most are quite faint and the westering Moon will interfere, but sharp-eyed observers will enjoy it.
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Tonight let’s have a look at a very bright and changeable lunar feature that is often over-looked. Starting with the great grey oval of Grimaldi, let your eyes slide along the terminator towards the south until you encounter the bright crater Byrgius. Named for Joost Burgi, who made a sextant for Tycho Brahe, this “seen on the curve” crater is really quite large with a diameter of 87 kilometers. Perhaps one of the most interesting features of all is high albedo Byrgius A, which sits along its east wall line and produces a wonderfully bright ray system. While it is not noted as a lunar club challenge, it’s a great crater to help add to your knowledge of selenography!
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Now let’s try a visual double for the unaided eye – Eta Virginis. Can you distinguish between a 4th and 6th magnitude pair?
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The brighter of the two is Zaniah (Eta), which through occultation had been discovered to be a triple star. In 2002, Zaniah became the first star imaged by combining multiple telescopes with the Navy Prototype Optical Interferometer. This was the first time the three were split. Two of them are so close that they orbit in less than half the distance between the Earth and Sun!
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Binocular users should take a look at visual double Rho Virginis about a fistwidth west-southwest of Epsilon. This pair is far closer and will require an optical aid to separate. The brighter of this pair – Rho – is a white, main sequence dwarf with a secret… It’s a variable! Known as a Delta Scuti type, this odd star can vary slightly in magnitude in anywhere from 30 minutes to two and a half hours as it pulsates.
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For mid-to-large telescopes, Rho offers just a little bit more. The visual companion star has a visual companion as well! Less than a half degree southwest of Rho is a small, faint spiral galaxy – NGC 4608 (Right Ascension: 12 : 41.2 - Declination: +10 : 09) – at 12th magnitude, it’s hard to see because of Rho’s brightness…but it’s not alone. Look for a small, but curiously shaped galaxy labeled NGC 4596 (Right Ascension: 12 : 39.9 - Declination: +10 : 11). Its resemblance to the planet Saturn makes it well worthwhile!
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Until next week? Ask for the Moon, but keep on reaching for the stars!
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<i>Written by Tammy Plotner</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-38722208882840510822012-05-23T14:26:00.001-07:002012-05-23T14:26:24.869-07:00Observing Alert - Supernova 2012cg Discovered In Virgo Galaxy NGC 4424<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifzOcy7wPEmZxEyRDGU3-87dmuIxRCwvlCqx0MYTL3a6sOexrWAkdHH47aEh6zXwpkdHf5X9HGHP9zh8kq0E5LlepUtUAxG4Qk_Fk-mCSedkggfnw_uPKoye8dFFVn72iyWPyi6Vqxq3PR/s1600/SN+2012cg.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="187" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifzOcy7wPEmZxEyRDGU3-87dmuIxRCwvlCqx0MYTL3a6sOexrWAkdHH47aEh6zXwpkdHf5X9HGHP9zh8kq0E5LlepUtUAxG4Qk_Fk-mCSedkggfnw_uPKoye8dFFVn72iyWPyi6Vqxq3PR/s400/SN+2012cg.jpg" /></a></div>
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It's official. According to AAVSO Special Notice #283 compiled by Elizabeth O. Waagen, there's a brand new, shiny supernova out there... at an observable magnitude! According to data taken with LOSS and reported by M. Kandrashoff, S. B. Cenko, W. Li, and A. V. Filippenko, spectra indicates a Type 1a supernova event began on approximately May 17, 2012 and has continued to brighten. <a name='more'></a>
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Cataloged as Supernova 2012cg, the event is visible in barred spiral galaxy, NGC 4424 located in the constellation of Virgo. Coordinates are RA 12 27 12.83 - Dec. +09 25 13.2. The supernova began erupting at an unfiltered magnitude of 16.9 and has now reached magnitude 12.9.
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Spectra indicating the object to be a Type Ia supernova discovered about two weeks before maximum were obtained by: L. Pei, M. Nguyen, D. Carson, and A. J. Barth (University of California, Irvine) with the Kast double spectrograph on the
Shane 3-m telescope at Lick Observatory on 2012 May 18 UT and reported by S. B. Cenko, A. V. Filippenko, and J. M. Silverman (University of California, Berkeley), and A. Gal-Yam (Weizmann Institute of Science); and J. Irwin with the F. L. Whipple Observatory 1.5-m telescope (+ FAST) on 2012 May 18 UT and reported by G. H. Marion, R. P. Kirshner, and R. J. Foley (Harvard-Smithsonian Center for Astrophysics, CfA), and P. Challis (Australian National University) on behalf of the CfA Supernova Group.
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Originally discovered on February 27, 1865, by Heinrich d'Arrest, NGC 4424 is a 12th magnitude barred spiral whose recessional velocity of 435 km/sec isn't aggressive enough to obtain an accurate distance measurements.Current consensus places the distance to be approximately 50 million light years, making its apparent size of 3.6 by 1.8 arc minutes to measure out to about 50,000 light years in diameter. According to a study done by R. Winnick and J. Kenney, NGC 4424 is " believed to be one of the clearest cases for a significant merger in the Virgo cluster. The R and B-band images reveal banana-shaped isophotes, which are thought to have resulted from a significant and recent merger. New spectra from the DensePak fiber array reveal double-peaked stellar absorption lines within the galaxy. These double-peaked features indicate the existence of co-spatial, counter-rotating stellar components within NGC 4424, further strengthening the merger theory."
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Catch a supernova in a most unusual galaxy!
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<i>Submitted by Tammy Plotner. Image Credit: Dr. Joe Brimacombe, Coral Towers Observatory, Cairns, AU</i>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-1782374334365610204.post-7063885340759874822012-05-21T12:10:00.000-07:002012-05-21T12:11:39.975-07:00Weekly SkyWatcher's Forecast: May 21-27, 2012<a href="http://www.universetoday.com/wp-content/uploads/2012/05/NGC-4038.gif"><img src="http://www.universetoday.com/wp-content/uploads/2012/05/NGC-4038-578x580.gif" alt="" title="NGC 4038" width="578" height="580" class="size-medium wp-image-95317" /></a>
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Greetings, fellow SkyWatchers! Here's hoping you had an opportunity to witness yesterday's eclipse! Even the partial phase here in Ohio was exciting... and to be able to watch virtually via live feeds was equally impressive! The week begins with dark skies and deep studies. Get up early to enjoy the apparition of Jupiter and Mercury just ahead of the rising Sun and check out Venus as it dances near the Earthshine Moon. When you're ready to observe, meet me in the back yard! <a name='more'></a>
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<b>Monday, May 21</b> – In 1961, United States President John F. Kennedy launches the country on a journey to the Moon as he makes one of his most famous speeches to Congress: “I believe this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space...”
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Tonight we’ll take an exploration of space as we study an interacting pair of galaxies. All that is required is that you find 31 Corvii, an unaided eye star west of Gamma and Epsilon Corvii. Now we’re ready to nudge the scope about one degree north. The 11th magnitude NGC 4038/39 (Right Ascension: 12 : 01.9 - Declination: -18 : 52) is a tight, but superior pair of interacting galaxies. Often referred to as either the “Ringtail” or the “Antenna”, this pair deeply captured the public’s imagination when photographed by the Hubble. (Unfortunately, we don’t have the Hubble - that's why I used a more "natural image", but what we have is set of optics and the patience to find them.) At low power the pair presents two very stellar core regions surrounded by a curiously shaped nebulosity. Now, drop the power on it and practice patience – because it’s worth it! When that perfect moment of clarity arrives, we have crackling structure. Unusual, clumpy, odd arms appear at strong aversion. Behind all this is a galactic “sheen” that hints at all the beauty seen in the Hubble photographs. It’s a tight little fellow, but worth every moment it takes to find it.
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<b>Tuesday, May 22</b> – Celestial scenery alert! If you’re up before dawn this morning, look for the very close pairing of Jupiter and Mercury racing together just ahead of sunrise. The disparate pair will be less than half a degree apart. It’s worth getting up early for!
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Tonight the slender crescent Moon will make a very brief appearance at dusk along the western skyline. If your atmosphere is very steady, why not set the telescope down on it and look for some very unusual features that will soon wash out as the Sun overtakes the moonscape. Almost central along the eastern lunar limb, look for Mare Smythii and Mare Marginis to its north. Between them you will see the long oval crater Neper bordered by Jansky at the very limb. And speaking of the limb, did you notice bright Venus accompanying the Moon? It’s a splendid conjunction and well worth alerting friends, family and neighbors to watch for! But don’t delay... The pair will set quickly!
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Now let’s visit a galaxy very similar to our own Milky Way – NGC 2903 (Right Ascension: 9 : 32.2 - Declination: +21 : 30). Located less than two degrees south of Lambda Leonis, this magnificent 9.0 magnitude barred spiral can be spotted with binoculars from a dark location, and is easily seen in a small scope.
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While NGC 2903's size and central bar closely resemble our own galaxy’s structure, the Hubble Space Telescope crossed the 25 million light-year gap and found evidence of young globular clusters in its galactic halo – unlike our own old structures. This widespread star forming region is believed to be attributed to the gravity of the central bar. Small telescopes will show the bar as a lateral concentration across the central structure, while larger apertures will reveal spiral arms and condensed regions of innumerable stars.
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<b>Wednesday, May 23</b> – Tonight the Moon is a little bit older and brilliantly lit with earthshine. Power up and let’s go look for crater named for historian and theologian Denis Petau – Petavius!
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Located almost centrally along the terminator in the southeast quadrant, a lot will depend tonight on your viewing time and the age the moon itself. Perhaps when you look, you’ll see 177 kilometer diameter Petavius cut in half by the terminator. If so, this is a great time to take a close look at the small range of mountain peaks contained in its center as well as a deep rima which runs for 80 kilometers across its otherwise fairly smooth surface. To the east lies a long furrow in the landscape. This deep runnel is Palitzsch and its Valles. While the primary crater that forms this deep gash is only 41 kilometers wide, the valley itself stretches for 110 kilometers. Look for crater Haas on Petavius’ southern edge with Snellius to the southwest and Wrottesley along its northwest wall.
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Now let’s have a look at Iota Virginis. While there is nothing particularly special about this spectral F type star, it does reside in a very interesting field for low power. Enjoy the colors!
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<b>Thursday, May 24</b> – If you chose to scope tonight, we’re going in search of another lunar club challenge that will prove difficult because you’ll be working without a map. Relax! This will be much easier than you think. Starting at Mare Crisium, move along the terminator to the north following the chain of craters until you identify a featureless oval that looks similar to Plato seen on a curve. This is Endymion…and if you can’t spot it tonight don’t worry. We’ll take a look in the days ahead at some features that will point you to it!
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While the Moon is still west, let’s have a look at telescopic star W Virginis located about three and a half degrees southwest of Zeta (RA 13 26 01.99 Dec -03 22 43.4). This 11,000 light-year distant Cepheid type variable is oddly enough a Population II star that lies outside the galactic plane. This expanding and contracting star goes through its changes in a little over 17 days and will vary between 8th and 9th magnitude. Although it is undeniably a Cepheid, it breaks the rules by being both out of place in the cosmic scheme and displaying abnormal spectral qualities!
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<b>Friday, May 25</b> – Tonight let’s take our own journey to the Moon as we look at a beautiful series of craters – Fabricius, Metius and Rheita.
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Bordered on the south by shallow Jannsen, lunar club challenge Fabricius is a 78 kilometer diameter crater highlighted by two small interior mountain ranges. To its northeast is Metius, which is slightly larger with a diameter of 88 kilometers. Look carefully at the two. Metius has much steeper walls, while Fabricius shows differing levels and heights. Metius’ smooth floor also contains a very prominent B crater on the inside of its southeast crater wall. Further northeast is the lovely Rheita Valley which stretches almost 500 kilometers and appears more like a series of confluent craters than a fault line. 70 kilometer diameter crater Rheita is far younger than this formation because it intrudes upon it. Look for a bright point inside the crater which is its central peak.
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Now let’s go revisit Omega Centauri. At magnitude 3.7, NGC 5139 (Right Ascension: 13 : 26.8 - Declination: -47 : 29) is one of the few studies in the night sky receiving a Greek letter despite being decidedly “unstarlike!”
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Recorded by Ptolemy as a star, given the designation “Omega” by Bayer, and first noted as non-stellar by Edmond Halley in 1677, J.L.E. Dreyer went on to add three exclamation marks (!!!) to his abbreviated description after including it as entry 5139 in the 1888 New General Catalogue. As the largest globular cluster in our own galaxy, this 5 million solar mass “star of stars” contains more matter than Sagittarius A – the supermassive black hole on which the Milky Way pivots. Omega’s mass is greater than some dwarf galaxies. Of the more than thirty galaxies associated with our Local Group, only the Great Andromeda possesses a globular (G1) brighter than Omega!
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<b>Saturday, May 26</b> – Tonight the Moon will be our companion. Now well risen above atmospheric disturbance, this would be a great time to have a look for several lunar club challenges that you might have missed.
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Most prominent of all will be two craters to the north named Atlas and Hercules. The eastern-most Atlas was named for the mythical figure which bore the weight of the world on his shoulders, and the crater spans 87 kilometers and contains a vivid Y-shaped rima in the interior basin. Western Hercules is considerably smaller at 69 kilometers in diameter and shows a deep interior crater called G. Power up and look for the tiny E crater which marks the southern crater rim. North of both is another unusual feature which many observers miss. It is a much more eroded and far older crater which only shows a basic outline and is only known as Atlas E.
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If you want to continue with tests of resolution, why not visit Theta Virginis? It might look as close as the Moon, but it’s only 415 light-years away from Earth! The primary star is a white A-type subgiant, but it’s also a spectroscopic binary of two companions which orbit each other about every 14 years. In turn, this is orbited by a 9th magnitude F-type star which is a close 7.1 arc-seconds away from the primary. Look for the fourth member of the Theta Virginis system well away at 70 arc-seconds, but shining at a feeble magnitude 10.4.
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<b>Sunday, May 27</b> – Tonight no two lunar features in the north will be more prominent than Aristoteles and Eudoxus. Why not revisit them? Viewable even in small binoculars, let’s take a closer look at larger Aristoteles to the north.
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As a Class 1 crater, this ancient old beauty has some of the most massive walls of all lunar features. Named for the great philosopher, it stretches across 87 kilometers of lunar landscape and drops below the average surface to a depth of 366 meters – a height which is similar to Earth’s tallest waterfall, the Silver Cord Cascade. While it has a few scattered interior peaks, the crater floor remains almost unscarred. As a telescopic lunar club challenge, be sure to look for a much older crater that sits on Aristoteles eastern edge. Tiny Mitchell is extremely shallow by comparison and only spans 30 kilometers. Look carefully at the formation, for although Aristoteles overlaps Mitchell, the smaller crater is actually part of the vast system of ridges which supports the larger.
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When you’re done, let’s have a look at another delightful pair that’s joined together – Gamma Virginis...
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Better known as Porrima, this is one cool binary with almost equal spectral types and brightnesses. Discovered by Bradley and Pound in 1718, John Herschel was the first to predict this pair’s orbit in 1833 and state that one day they would become inseparable to all but the very largest of telescopes – and he was right. In 1920 the A and B stars had reached their maximum separation, and during 2007 they will be as close together as they will ever be. Observed as a single star in 1836 by William Herschel, its 171 year periastron will put Porrima in the exact position now as it was when Sir William saw it!
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Until next week? Ask for the Moon... But keep on reaching for the stars!
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<i>Written by Tammy Plotner. Image Credit: NGC 4038/39 - Palomar Observatory Courtesy of Caltech</i>Unknownnoreply@blogger.com0