Friday, February 25, 2011

Weekend SkyWatcher's Forecast - February 25-27, 2011

Written By Tammy Plotner

Greetings, fellow SkyWatchers!

Well, if you're not buried in snow, blown away by tornadoes, or just suffering under clouds and rain, why not take advantage of mostly dark skies and enjoy some astronomy! Whether you use binoculars, a small telescope, love to astro-image or just like to kick back and stargaze - there's something here for everyone to enjoy!

Now, relax. And let's journey...

Friday, February 25, 2011 - The absence of early evening Moon is a great time for obscure objects requiring dark skies. Locate Epsilon Monocerotis and
head three finger-widths northeast for a vast complex of nebulae and star clusters. Variable binary S Monocerotis is easily visible, and small binoculars will find the beginnings of a rich cluster surrounding it: NGC 2264 (RA 06 41 00 Dec +09 53 00). Larger binoculars and small telescopes will detect a distinct wedge of stars—the 2-million-year-old Christmas Tree Cluster. Its nebulosity is beyond a small telescope, but the brightest portion is the Cone Nebula.

The northern region—the photographic-only Foxfur Nebula—is part of a vast complex extending from Gemini to Orion. Northwest are several regions of bright nebulae. Best suited to the average scope is large, faint NGC 2245, which accompanies an 11thmagnitude star. Fog-like NGC 2247 is a circular patch of nebulosity around an 8th magnitude star. IC 446 is for larger aperture, appearing comet-like with nebulosity fanning away southwest. Even to a large scope, the ‘‘barely there’’ IC 2169 is most difficult of all!

Return to Epsilon Monocerotis, and move a finger-width east for another star field with an interesting companion. NGC 2244 (RA 06 31 54 Dec -04 56 00) is a galactic cluster embroiled in a reflection nebula commonly called the ‘‘Rosette.’’ The cluster stars heat the nebula’s gases to nearly 10,000 degrees Celsius, emitting light in a process similar to fluorescence. A huge percentage of this light is hydrogen-alpha; backscattered from its dusty shell and polarized. You won’t see any red hues, but with good seeing, small telescopes can detect a broken, patchy wreath of nebulosity around the well-resolved symmetrical concentration of stars crowned by the yellow jewel of 12 Monocerotis. Larger scopes, and filtered ones, will make out separate areas, which also bear their own distinctive NGC labels. The entire region is one of the best for winter skies!

Saturday, February 26, 2011 - Today we celebrate the birth on this date of many astronomers, starting in 1786 with Francois Arago, who discovered the solar chromosphere and made astonishingly accurate estimates of planetary diameters. Arago’s experiments proved the wave theory of light and contributed to the laws of polarization. Following in 1842 was astronomer and author Camille Flammarion, who studied multiple stars, the Moon, and Mars. Although erroneous in some observations (‘‘May we attribute to the color of the herbage and plants which no doubt clothe the plains of Mars, the characteristic hue of that planet...’’), Flammarion was entrusted with a personal copy of the Messier Catalog, including the author’s notes, which he later revised. Last is the 1864 birth of John Evershed, who contributed mightily to solar physics when he photographically discovered that gases in sunspots flowed horizontally from the center toward their edges, an effect now named for him!

Let’s celebrate them all by kicking up some stardust about 5 degrees south of Alpha Monocerotis and into Puppis for M46 (RA 07 41 42 Dec -14 49 00).

Containing around 150 resolvable stars, and possibly involving as many as 500, this cluster appears faint and compressed to binoculars, but one star seems brighter than the rest. Through the eye of a telescope, you’ll soon discover the reason! In its northern portion, the 300-million-year old M46 contains a planetary nebula known as NGC 2438, first noted by Sir William Herschel. While it would appear to be a member of the cluster, the planetary nebula is just a little closer to us than the stars. Be sure to mark your notes. There’s a lot to find in just a little area!

Afterwards, relax and enjoy the Delta Leonid meteor shower. Burning through our atmosphere at speeds of up to 24 kilometers per second, these slow travelers will seem to radiate from a point around the middle of Leo’s ‘‘back.’’ The fall rate is rather low at around 5 per hour, but they are still worth keeping a watch for!

Sunday, February 27, 2011 - Today let’s celebrate the 1897 birth on this date of Bernard Lyot, master of optics. He invented the polariscope, and produced the first solar coronagraph. He also made the first motion pictures of solar prominences. Lyot was an astute observer, and realized that the lunar surface had similar properties to volcanic dust. He didn’t see canals on Mars but observed sandstorms there, as well as atmospheric conditions on other planets. The Lyot filter is well known, and so is his micrometer, a device used to make precise distance measurements, especially those between close double stars. By all accounts a wonderful and generous man, Lyot sadly died of a heart attack while returning from seeing an eclipse.

Honor Lyot’s work by studying two open clusters, found about a fist-width north of Xi Puppis. The brighter of the two— M47 (RA 07 36 36 Dec -14 29 00) —is 1,600 light-years away and a glorious object for binoculars.

Filled with mixed-magnitude stars that resolve fully to aperture, M47 features the matched-magnitude double star Struve 1211 near its center. For all its bright beauty, this stellar swarm has the most ironic of histories. Probably discovered first by Hodierna but kept secret, it was independently recovered by Charles Messier, but its position was logged incorrectly. Later, it was cataloged by both William and Caroline Herschel. . .and yet again by John Herschel, who said: ‘‘This cluster has not since been observed. It is probably very loose and poor one.’’ Even Dreyer had a hard time nailing it down! Funny, considering it has only been there for 78 million years...

While M47 is a Herschel object, look just slightly north (about a field of view) to pick up another cluster that borders it, NGC 2423 (RA 07 40 45 Dec -19 09 00). This compressed cluster contains more than two dozen faint stars with a lovely golden binary at its center. By comparing the two clusters telescopically, you are also expanding your own studies by viewing two different types of stellar evolution: M47 is very similar to the Pleiades, while NGC 2423 more closely resembles the Hyades.

Have a great weekend!

Astronomical Image Credits - Palomar Observatory, courtesy of Caltech. Historical Images are Public Domain.

Wednesday, February 23, 2011

Venus, Moon and Morning Coffee...

Written by Tammy Plotner

If you’re an early riser, then perhaps you’ve noticed Kepler’s Laws in action? No, it’s not a new Bruce Willis movie, just the inevitable pairing of the waning crescent Moon and shining Venus. As you can see from this great photo taken last month by John Chumack, it happens as regular as clockwork… and it’s about to happen again. But what is it about such pairings that command our attention? Let's find out...

According to the Sky & Telescope press release, the brightest planet and the eerie waning crescent Moon will create an arresting sky scene low in the southeast in the early dawn of Monday, February 28th, and Tuesday, March 1st. “These are the two brightest astronomical objects in the sky after the Sun,” says Alan MacRobert, a senior editor of Sky & Telescope magazine. “They’ll certainly catch your eye, if you look low in the southeast about 60 to 40 minutes before sunrise — weather permitting.”

Venus will be shining to the Moon’s lower left on the morning of Monday Feb. 28th. The next morning Venus will be to the Moon’s right or upper right. Although they look close together, they’re not. Venus is currently 400 times farther away than the Moon. It’s at a distance of 8.8 light-minutes (the distance light takes to travel that far), compared to the Moon’s distance of 1.3 light-seconds. In miles, that’s 99 million miles for Venus and just 249,000 miles for the Moon. (In fact, you may have driven cars enough miles to get to the Moon.) And despite appearances, Venus is 3½ times wider than the Moon’s diameter.

“Why do people care about this?” asks MacRobert. “Because some people know we need to look up beyond our own little world — and recognize where we are as part of nature, part of the universe. So many of us live our busy little ant-hill lives without ever noticing the gigantic universe beyond the anthill. A lot of people don’t even know you can see alien planets from your driveway while you’re unlocking the car to go to work.”

But just what is it about such a celestial scene that draws our eye like no other? When it comes to our eyes, almost every photoreceptor has one ganglion cell receiving data in the fovea. That means there’s almost no data loss and the absence of blood vessels in the area means almost no loss of light either. There is direct passage to our receptors – an amazing 50% of the visual cortex in the brain! Since the fovea doesn’t have rods, it isn’t sensitive to dim lights. That’s another reason why the conjunctions are more attractive than the surrounding starfields. Astronomers know a lot about the fovea for a good reason: it’s is why we learn to use averted vision. We avoid the fovea when observing very dim objects in the eyepiece.

“Your eye is like a digital camera,” explains Dr. Stuart Hiroyasu, O.D., of Bishop, California. “There’s a lens in front to focus the light, and a photo-array behind the lens to capture the image. The photo-array in your eye is called the retina. It’s made of rods and cones, the fleshy organic equivalent of electronic pixels.” Near the center of the retina lies the fovea, a patch of tissue 1.5 millimeters wide where cones are extra-densely packed. “Whatever you see with the fovea, you see in high-definition,” he says. The fovea is critical to reading, driving and even watching television. The fovea has the brain’s attention. The field of view of the fovea is only about five degrees wide.” When Venus and the crescent Moon are close to that narrow angle, it signals to the brain, “this is worth watching!”

Let’s pretend we’re a photoreceptor. If a light were to strike us, we’d be “on” – recording away. If we were a ganglion cell, the light really wouldn’t do much of anything. However, the biological recorder would have responded to a pinpoint of light, a ring of light, or a light with a dark edge to it. Why? Light in general just simply doesn’t excite the ganglion, but it does wake up the neighbor cells (as does hooting and screaming while pointing at the morning sky). A small spot of light makes the ganglion go crazy, but the neighbors don’t pay much attention (unless you’re in your pajamas cleaning the snow off your car). However, a ring of light makes the neighbors go nuts (and their dogs) and the ganglion turns off. It’s all a very complicated response to a simple scene, but still fun to understand why we are compelled to look!

And perhaps howl just once.

Many thanks to John Chumack of Galactic Images and to Sky & Telescope Magazine for the heads up!

Saturday, February 19, 2011

Sunspot Activity Hasn’t Stopped Yet

Written by Tammy Plotner

According to SpaceWeather: “Fast-growing active region 1161 erupted on the morning of February 18, producing an M6.6-class solar flare at 1011 UT. The almost-X category blast was one of the strongest flares in years and continued the week-long trend of high solar activity.” Just how awesome is that? Then take a look at these white light solar images done by John Chumack…

While today’s activity isn’t supposed to impact Earth in a negative manner, who knows what it might produce in the days ahead? Just ask NOAA!

“A G1 (minor) geomagnetic storm continues. What might have been three hits of shocks/CMEs seems to have merged to be just one interplanetary shock/CME structure. Look for about another day’s worth of geomagnetic activity, pending additional treats in the solar wind. Elsewhere Region 1158 had another R2 (moderate) radio blackout, and fast-growing new Region 1162 likely generated an R1 (minor) event.”

With 1158 nearing the limb and wonderfully active, now is the time for solar observers to try and catch the “Wilson Effect” – an effect in which the penumbra of a sunspot appears narrower in the direction toward the Sun’s center.

While you’re at it, it doesn’t hurt to keep watch for auroral activity tonight and in the days ahead – despite the lunar interference. With satellite communications impacted in my area, I’m anxious to see what the nights – and days – bring!

Many thanks to John Chumack of Galactic Images for sending some "sunlight" my way!

Friday, February 18, 2011

The Snow Moon: February's Chilly Full Moon Arrives

Contributed by R.D. Stephens

While doing some stargazing reading for kicks, I found out that each of the month's full moons have a name and a meaning which I found interesting and it led me to a slew of short stories and fables from several North American tribes. So I've decided to write a little once a month about the different moon 'names' and stories tied to them.  Hope you enjoy!

February, not surprisingly, is often known as the Snow, Wolf or Bone Moon because this is usually the snowiest, coldest and for native peoples of the past the hungriest time of year.  Of course in Southern California it was near 90 degrees this past week so we can't really relate, or complain- go ahead, be jealous-  The harsh fact of the mid-winter lack of food naturally led to moral stories about why to avoid being out on nights of the full moon. Turns out it's not just because the viewing isn't the greatest.  This month's full moon, by the way, wont' be rising until 2:30 or so in the morning so you have plenty of dark time between sunset and then.

The Cherokee call this moon the Bone Moon and marked the night with a feast set with places for their deceased ancestors to dine with them. It was a time to take notice of the previous deaths, honor those people and hope that the rest of the family would carry through.   This moon was also tied to the wolves by several tribes marking when their hunger seemed at it's worst and they became so desperate for food  they would risk attacking people.  Though all rather dismal, this moon also marked the end of the worst of winter for many tribes as well.  The days will start to grow warmer and longer, Spring is just around the corner.

Friday, February 11, 2011

Weekend SkyWatcher's Forecast - February 11-13, 2011

Written by Tammy Plotner

Friday, February 11 - With the Moon looming high overhead as darkness falls, this looks like a good weekend to explore our nearest astronomical neighbor! Tonight we will begin our lunar explorations as we look to the far north and identify the “Sea of Cold”—Mare Frigoris. This long, vast lava plain extends 1126 kilometers across the surface from east to west, yet never ranges more than 72 kilometers from north to south. Look for the unmistakable dark ellipse of landmark crater Plato caught on Frigoris' southern central shore.

Plato Crater - Credit: Damien Peach

Named after the famous philosopher, this mountain-walled plain with a dark floor is a Class V crater. Its slightly oval shape spans approximately 101 kilometers in diameter but is a shallow 1 kilometer deep - .appearing far more elliptical due to its northern latitude. Plato's floor is its most curious feature. Consisting of 2,700 square miles of unique lava, and only broken by a couple of very minor and supremely challenging craters, Plato is one of the very few areas on the lunar surface that seems to have changed in recent history. The bright rim of Plato's enclosure is very ragged and can rise as high as 2 kilometers above the surface, casting unusual shadows on the lava covered floor. At around 3 million years old, Plato is more ancient than Mare Imbrium to its south. For 300 years astronomers have been keeping a watchful eye on this crater. Hevelius called it the “Greater Black Lake,” due its low albedo (surface reflectivity). Despite its dark appearance, Plato is well known as a home for lunar transient phenomena such as flashes of light, unusual color patterns and areas that could be outgassing. Enjoy this lunar feature which will point the way to others in the future!

Saturday, February 12 - Let's begin our lunar studies tonight with a deeper look at the "Sea of Rains." Our mission is to explore the disclosure of Mare Imbrium, home to Apollo 15. Stretching out 1123 kilometers over the Moon's northwest quadrant, Imbrium was formed around 38 million years ago when a huge object impacted the lunar surface creating a gigantic basin.

The basin itself is surrounded by three concentric rings of mountains. The most distant ring reaches a diameter of 1300 kilometers and involves the Montes Carpatus to the south, the Montes Apenninus southwest, and the Caucasus to the east. The central ring is formed by the Montes Alpes, and the innermost has long been lost except for a few low hills which still show their 600 kilometer diameter pattern through the eons of lava flow. Originally the impact basin was believed to be as much as 100 kilometers deep. So devastating was the event that a Moon-wide series of fault lines appeared as the massive strike shattered the lunar lithosphere. Imbrium is also home to a huge mascon, and images of the far side show areas opposite the basin where seismic waves traveled through the interior and shaped its landscape. The floor of the basin rebounded from the cataclysm and filled in to a depth of around 12 kilometers. Over time, lava flow and regolith added another five kilometers of material, yet evidence remains of the ejecta which was flung more than 800 kilometers away, carving long runnels through the landscape.

Crater Eratosthenes – Credit: Damien Peach

Look along south shore of Mare Imbrium right where the Apennine mountain range meets the terminator. At 58 kilometers in diameter and 12,300 feet deep, Eratosthenes is an unmistakable landmark crater. Named after the ancient Greek mathematician, geographer and astronomer Eratosthenes, this splendid crater will display a bright west wall and a black interior hiding its massive crater capped central mountain 3570 meters high! Extending like a tail, an 80 kilometer mountain ridge angles away to its southwest. As beautiful as Eratosthenes appears tonight, it will fade away to almost total obscurity as the Moon approaches full. See if you can spot it again in five days.

Sunday, February 13 - We start tonight's lunar tour with a northern landmark that can even be spotted with unaided vision - Plato. Located in the northern hemisphere of the Moon, its dark ellipse is unmistakable. Plato's floor consists of 2700 square miles of lava fill and is considered by some observers as the darkest single low-albedo feature on the Moon. Because of its low reflectivity, this crater has the distinction of being one of the only mountain-walled plains that doesn't "disappear" as the Moon grows full. With Plato in the center of the field note the pyramid-like peak of Pico due south in northeastern Mare Imbrium. East of Pico is an unnamed dorsum - or lava wave - terminating just above crater Piazzi Smyth to the south. Power up in a telescope and check out the triangular peak near its end.

Sinus Iridum – Credit: Peter Lloyd

Now let's go to the lunar surface to have a look through binoculars or telescopes at tremendous impact region located to the lunar west of Plato. Sinus Iridum is one of the most fascinating and calming areas on the Moon. At around 241 kilometers in diameter and ringed by the Juras Mountains, it's known by the quiet name of the Bay of Rainbows, but was formed by a cataclysm. Astronomers speculate that a minor planet around 200 kilometers in diameter impacted our forming Moon at a glancing angle, and the result of the impact caused "waves" of material to wash up to a "shoreline," forming this delightful C-shaped lunar feature. The impression of looking at an earthly bay is stunning as the smooth inner sands show soft waves called "rilles," broken only by a few small impact craters. The picture is completed by Promontoriums Heraclides and LaPlace, which tower above the surface, at 1800 meters and 3000 meters respectively, and appear as distant "lighthouses" set on either tip of Sinus Iridum's opening. For a great telescopic challenge, imagine that Sinus Iridum is a mirror focusing light - this will lead your eye to crater Helicon. The slightly smaller crater southeast of Helicon is Leverrier. Be sure to power up to capture the splendid north-south oriented “wave -like” ridge which flows lunar east. Enjoy this serene feature ...

And enjoy your weekend!

Friday, February 4, 2011

Weekend SkyWatcher's Forecast - Playin' In Puppis

Written by Tammy Plotner

With very little Moon to contend with this weekend, why not spend some quality time with the Pup? Dust off those binoculars, set up that telescope! It's time to dance in the dark...

The constellation of Puppis once belonged to a much larger constellation known as Argo Navis – the mythological ship used by Jason and the Argonauts. Argo Navis was recognized as one of the original 48 constellations charted by Ptolemy, but was later subdivided in 1752 by Nicolas Louis de Lacaille into three sections and renamed into Carina (the keel of the ship), Puppis (the poop deck), and Vela (the sails). Because Bayer Flamsteed designations were already in use at the time, the designations were also split, with each constellation taking the Argo Navis designation with it – such as Alpha and Beta belonging to Carina – while Vela has Gamma and Delta. After officially being listed as one of the 88 modern constellation by the International Astronomical Union, Puppis now occupies 673 square degrees of sky and ranks 20th in constellation size from its position just south of the ecliptic plane. Puppis is bordered by the constellations of Monoceros, Pyxis, Vela, Carina, Pictor, Columba, Canis Major and Hydra It contains 76 Bayer Flamsteed stars within its confines and its primary asterism is composed of 9 main stars. Puppis is visible to all observers located at latitudes between +40° and ?90° and is best seen at culmination during the month of February.

There are three minor annual meteor showers associated with the constellation of Puppis. Beginning each year on about April 15 through April 28, you can watch for activity from the Pi Puppids, with the peak date of maximum activity on or about April 23. The meteoroid stream is very irregular and the fall rate is variable. The Zeta Puppids begin activity around November 2 and end around December 20th with a peak date of on or about November 13th. This is also a very weak meteoroid stream which produces no more than about 3 meteors per hour at maximum. The Puppid-Velid meteor shower begins around December 2 and lasts through December 16th with a peak date on or about December 12. While this is also an understudied meteor shower, it does have a slightly more productive rate at a maximum of 4 meteors per hour during peak activity. The radiant for this shower is very complex, so keep an eye out in the whole general area. It contains several substreams and may have several different times of maxima.

As a section of the great ship Argo Navis, the mythology of Puppis is the legend of the great sea and the adventures of Jason and the Argonauts. The great galley was built under the orders of the goddess Athene, where she then fitted a beam into the prow from the oracle of Zeus. On board was a crew of Greek heros, including such notable mythological figures such as Hercules, Castor and Pollux. Of course, their journeys were legendary, and after having acquired the golden fleece they dedicated the ship to the sea god Poseidon, who immortalized it in the stars and the first of the ocean-going vessels. Due to it’s enormous size, early cartographers often had difficulty portraying it on star charts and its magical prow had disappeared. The mariner’s compass, the constellation of Pyxis, was also once considered a part of Argo Navis, too… But has also been divided away with time. As for Puppis the Poop Deck? Actually, being on the roof of the stern cabin is a mighty fine place to be if you’re sailing amongst the stars….

Let’s begin our binocular tour of Puppis with a look at the bright star right in the middle – Zeta. Named Naos, which means “ship”, this grand spectral class is O5Ia star is one of the hottest known that is visible to the unaided eye. Punching in with a surface temperature of 42,400 K, what you are looking at is an extreme blue supergiant star – one of the brightest stars in the Milky Way Galaxy! At a distance of about 1400 light years from Earth, it doesn’t appear to be that impressive, but if it were as close as Sirius, it would light up our nights bright enough to cause shadows! Putting of 21,000 times more visible light and 790,000 times more light across the spectrum than our own Sun, this incredible star would absolutely vaporize our Earth if it were anywhere near our solar system. In several hundred thousand years, Naos will begin to cool and eventually become a red supergiant star. When it ends its life in a couple of million years, chances are it will go hypernova – forming a black hole and eventually a new nebula for starbirth in the never-ending cycle of cosmic wonder. What causes it to be so unusual? There’s evidence that Noas is a “runaway star“… once formed in the Vela region and now 400 light years away from the womb.

Now, let’s begin in the north with binoculars for a look at open cluster Melotte 71 (RA 07:37:30 Dec -12:03:06). This outer disc cluster is also known as Tombaugh 2 and will show as a compression of stars in binoculars and reveal about 80 or so members to mid-sized telescopes at low magnification. It is fairly rich and contains several reddish stars.

Keep your binoculars handy, or stick with the scope for Messier 46 (RA 07: 41.8 Dec ?14:49). This grand galactic star cluster was discovered by Charles Messier in 1771. Located about 5500 light years away from Earth, you’ll find about 150 stars spread over a 30 light year wide area… But one will stand out from the rest. Good reason – it’s a planetary nebula! Planetary nebula NGC 2438 will appear at the cluster’s northern edge and is probably just in the line of sight since it does not share the same velocity as M46.

Do you see other open cluster nearby? That’s Messier 47 (RA 07:36.6 Dec -14:30). It was discovered by Giovanni Batista Hodierna before 1654 and independently discovered by Charles Messier on February 19, 1771 and added to the Messier Catalog. While it contains only about 50 or so stars, it’s much brighter and more well resolved in smaller optics. Not bad for being 78 million years old!!

Stick to the telescope to discover NGC 2440 (RA 07:41: 54.91 Dec -18:12:29.7). This planetary nebula has a central star with an exceptionally high surface temperature of 200,000 kelvins. Studied by the Hubble Space Telescope for its strange bow shape, NGC 2440 has a complex structure with dense ridges of material swept back from the nebula’s central star.

Take your telescopes or binoculars out and look just north of Xi Puppis (RA 07 44 36 Dec -23 52 00) for a “mass concentration” of starlight known as Messier 93. Discovered in March of 1781 by Charles Messier, this bright open cluster is a rich concentration of various magnitudes which will simply explode in sprays of stellar fireworks in the eyepiece of a large telescope. Spanning 18 to 22 light-years of space and residing more than 3400 light-years away, it contains not only blue giants, but lovely golds as well. Jewels in the dark sky! As you view this open star cluster, seize the moment to remember Messier, because this is one of the last objects he discovered personally. He described it as “A cluster of small stars without nebulosity” – but did he realize the light he was viewing at the time left the cluster during the reign of Ramses III? Ah, yes…sweet time. Did Charles have a clue this cluster of stars was 100 million years old? Or realize it was forming about the time Earth’s land masses were breaking up, dinosaurs ruled, and the first mammals and birds were evolving? Although H. G. Wells “Time Machine” is a work of fiction, each time we view through a telescope we take a journey back across time itself. Enjoy the mystery!

Now, head off for NGC 2669 (RA 8 : 44.9 Dec -52 : 58). At magnitude 6, this 12 arc minute open cluster is a dazzling little gem that is on many southern sky observing lists… one that’s a study for proper motions! More? Then try Collinder 135. It is also a bright and dazzling open cluster that contains Pi Puppis and may have once been part of an OB cluster. Pick Pi out of the group… with a mass of between 13 and 14 solar masses, it will most likely explode in it’s future taking its binary star companion with it! Oddly enough, Collinder 135 wasn’t even recognized as an open star cluster until the Hipparchos satellite revealed that all the stars there were at a similar distance!

Are you ready for a globular cluster? Then try NGC 2298 (RA 6 : 49.0 Dec -36 : 00). At around magnitude 9 and 7 arc minutes in size this one will be a challenge for smaller optics. NGC 2298 was discovered by James Dunlop on May 30, 1826 and cataloged as Dunlop 578. It contains a lot of variable stars and it is on its way to disruption. According to Hubble Space Telescope studies, it’s losing mass.

For the big telescope, try your luck with NGC 2427 (RA 7 : 36.5 Dec -47 : 38). At around 11th magnitude and about 7 arc minutes in size, this super low surface brightness spiral galaxy won’t take to any kind of magnification, so use a low power eyepiece. Studies have shown it displays peculiar velocities in it’s HII regions and may display gravitation instability.

Don’t forget, Puppis is located right in the Milky Way, so there’s plenty more deep sky objects to go! Get yourself a good star map and explore…

Thursday, February 3, 2011

Checkmate... Capturing the "Steed of Dust"

Written by Tammy Plotner

Is there any place in the night sky which stimulates our imaginations more than the famous Horsehead? This area of dark dust painted over the smokey veil of emission nebula is one of the most often photographed and visually sought-after regions in Orion. How many of us have used (or bought) a special filter just to see it with your own eyes? Then behold it once again in all of its glory - and all of its mysteries...

"I am happy to present my first image of 2011 with an object that has been long on my target list." says astrophotographer, Ken Crawford. "This is the famous Horsehead Nebula which is formed by a dark cloud of dust and gas that forms a silhouette against the glow of IC434 behind it. There has been a lot of research done in this region because of the star forming fronts and surrounding molecular clouds with condensing areas that show up as small red clumps. These clumps are glowing red because of the rising temperatures inside are getting hot enough to be seen through the gas surrounding it as they become new stars. These condensing, glowing clumps are called Herbig-Haro objects and can be seen below the Horsehead on the left side and in the cropped image. There is a young new star in the top of the “head” area that sits in a small nebula and has the name B33-1."

But radiation from this hot star is eroding the stellar nursery. When E.E. Barnard discovered it in 1913, he noted that the edges were "sharp" and "well defined". Not any more. In just about a century the UV radiation of this O9 star is beginning to show its slow destruction of the cloud.... and that's not all that is eating away at the familiar equine shape. "We find evidence for a lozenge-shaped clump in the ‘throat’ of the horse, which is not seen in emission at shorter wavelengths. We label this source B33-SMM2 and find that it is brighter at submillimetre wavelengths than B33-SMM1." says D. Ward-Thompson, et al. "We calculate the stability of this core against collapse and find that it is in approximate gravitational virial equilibrium. This is consistent with it being a pre-existing core in B33, possibly pre-stellar in nature, but that it may also eventually undergo collapse under the effects of the HII region."

However, destruction is not all this beautiful image reveals. "The bright nebula in the lower left is called NGC2023 and is called a reflection nebula because the blue wavelengths of light are reflected by the dust and gas around the hot blue star." says Crawford. "There are also Herbig-Haro objects in this active region of star formation. This reflection nebula provides a beautiful contrast of textures and colors that help make the Horsehead nebula one of my all time favorites."

Checkmate, Ken... It's one of ours, too!

Many thanks to Ken Crawford for Imaging The Deep Sky and sharing it with us!

Wednesday, February 2, 2011

That's Right Woodchuck, Chuckers- It's GROUNDHOG DAY!

By R.D. Stephens

As most of us learned in grade school, if a groundhog emerges from his winter home today and sees his shadow, he'll dive back in for another six weeks of chilly weather but if the skies are cloudy and no shadow is seen, spring is on the way!  Of course, we know that the change in the seasons has nothing to do with what a chubby rodent might say about it but just how did the humble groundhog become the face of this tradition?

Like many of the holidays that are widely celebrated in the United States and Canada, Grounghog Day was a meld of several different traditions.  The Catholic holiday of Candlemas is February 2nd which celebrates an early period in Jesus' life, St. Brigid's Day which was an ancient Gaelic holiday marking the official first day of Spring, and a Pennsylvania Dutch tradition that was first documented in the mid 1800's that referenced a groundhog as the way to tell if spring were truly on its way or not. The first official Groundhog Day was in Punxsutawney, PA 1887 using the German folktale of the groundhog and his shadow to settle whether spring began on February 2nd or on the Vernal Equinox itself.  So an ancient difference in religious sentiments over the start of Spring now rests on a giant squirrel-like animal that, according to several sources, is 'right' about 40% of the time. Hmmmmm, Punxsutawney Phil- that's not exactly a passing grade.

And what does this have to do with the night sky? Not a darn thing but maybe we should all hope for a cloudy day this once, just in case Phil does know what he's doing.