Rigel Focusing Technology

By Tammy Plotner

Greetings, Earthlings!  Something new has arrived from Rigel and it's about to change your focus – your telescope's focus, that is!  Check out the USB-nSTEP and discover how you can computerize your stepper focus motor!

Rigel System's USB-nSTEP connects your unipolar stepper motor to your PC or MAC, for easy remote operation of your focuser.  Fully ASCOM compliant so it will work with popular focus control programs. Can be operated for temperature compensation with the optional temperature sensor (below). Full step and half step control from computer and display of step count. USB and 12V battery power cables included. Software and ASCOM drivers for Windows xp/vista/7 and soon for MAC. Approximately 1.5 inches wide by 4 inches long by 0.5 inches thick.  Just remember, the Focuser and Stepper motor not included. Compatible with Rigel Systems, Feathertouch, Robofocus & Moonlite stepper motors (please identify your stepper motor when purchasing).

Why use nSTEP?   A motorized focuser won’t shake the telescope while your focusing, and the motor can make very small rotations of the focus knob more reliably than you can by hand even with a speed reducer, but not just any DC motor and any DC focus motor controller.

Most other DC motor controllers control the motor speed by with a potentiometer you have to turn to reduce the voltage to the motor, which also reduces the torque, often to the point where the motor will not start turning the focuser knob.  So you have to use both hands, one to operate the button, one to adjust the potentiometer to high speed to get the motor started, then reduce it back down so it doesn’t turn too fast.  And of course the motor continues to coast after you've lifted your thumb off of the button, so by the time you've reacted to what you see in the eyepiece, it's too late.  nFOCUS provides pulse-width-modulation speed control.  Which means the length of the pulse of current to the motor can be adjusted shorter or longer, to produce from a 1° to 3° rotation of the focuser knob per step.  And it’s always a high-torque 12 volt pulse that provides plenty of oomph to reliably start the focuser shaft turning.  Step by step, degree by degree. And at the end of each pulse, nFOCUS electronically brakes the motor to a quick stop. nFOCUS also lets you select the length of the pauses between pulses.  With nFOCUS the focuser steps then pauses while you check the discrete changes in the focus before nFOCUS steps to the next focus position.  The pauses also give you time to lift your thumb off of the button so you don’t miss perfect focus!

And what about the Celestron CPC and HD focusers? The Rigel nFOCUS stepper motor and controller is the upgrade for you!

Motorize your Celestron focuser with our high torque 12V DC motor driven by our nFOCUS motor controller for the ultimate in accurate focusing. nFOCUS is the affordable way to get high precision fine focusing without vibration for visual and astro-imaging! Easier to use, more accurate, and a lot less money than the premium dual speed manual knob upgrades. Easily switch from motorized to manual focusing by loosening red thumb screws. Can be easily switched to our stepper motor.  Don't forget... the focuser isn't included – it's on your telescope!

The nFOCUS controller fits in the palm of your hand and provides two directions at two speeds with only two buttons using advanced logic control and 12V regulated output!

Low speed is adjustable pulse width modulated (PWM) drive, providing full voltage torque for reliable low speed operation.  Press the second button down while holding the first button down and nFOCUS digital logic control switches to high speed drive, to get you to focus quickly. nFOCUS avoids the problems with the focus motor controllers which adjust voltage to adjust speed, and thereby don't have the umph to turn the motor over at low speed. The nFOCUS whacks the motor with a full 12 volt, short duration pulse to overcome “stiction” at low speed operation, providing plenty of umph! It is amazing to see nFOCUS work, to see the focus change step by step till it's just right. No more coasting past then back past then past again. Uses 3 AA batteries (supplied) for long life.