System is designed for the greatest variety of mounts and motors and mechanical drive designs, including altazimuth mounts, equatorial mounts, GEMs (german equatorial mounts), siderostats. Any type of mechanical drive arrangement that yields a 300:1 to 10,000:1 reduction is acceptable. For stepper systems, use any type of unipolar stepper motor including small motors from old 5.25 inch floppy drives.
Handles a German Equatorial Mount flipping across the meridian.
Siderostat option: prevents mount from flipping over and instead moves scope past zenith.
Fast precise alignment to the sky.
Single (can be surplus) motor per axis.
Stepper system will control unipolar stepper motors via the available circuit board, and optionally can control other motor types that accept single step pulse and direction inputs. Stepper system also handles 5 phase motors. Servo system will control any servo motor with an attached optical encoder.
Simplest possible drive circuit.
Stepper system utilizes smooth microstepping tracking with up to 40 microsteps per fullstep. Here is a comment from a user on the smoothness of the 20 microsteps: "Increasing the number of microsteps from 10 to 20 was a superb improvement to your software ! You have basically eliminated the need to adjust the PWMs. Or at least. You have now rendered it extremely difficult to actually measure the PWMs variances. The motors run visibly smoother in tracking speed.". Here is a note from Chuck Shaw showing how accurate the drive can be in a portable scope: "I went to our dark sky location where we have the 32 inch Danciger newtonian and took my 14 with me to do some dark sky imaging. The drive system's performance was breathtaking!!!! I took 21 one minute exposures of M-101 at f/3.5 (14.5 inch f/5 system with a .7 focal reducer). When I went to do the track and stack operations, the TOTAL displacement from the first image to the 21st image was only 13 pixels....!!!! That is about 30 arcseconds over the almost 30 minutes it took to take the images!!!! Thats a drift rate of about 1 arcsecond/minute!!!!!! Incredible!!!!!!!!!!!! Do I love this system or what????"
Stepper system uses high speed overvoltage halfstep slewing, usually achieving 5,000 halfsteps per second, and up to 10,000 halfsteps per second (1800 rpm).
Servo system has large dynamic range. Given typical 512 count per revolution encoder that quadrature decodes to 2048 counts per revolution, and 5000 rpm servo motor, system can be designed for precise tracking at 0.1 arcsecond resolution yielding 4.7 degrees per second slews, to coarser tracking at 1 arcsecond per encoder count yielding an astounding 47 degrees per second slew rate.
Low current draw, typically 0.1 amps at 12 volts DC when either tracking or slewing.
Automatically refines the altitude reading based on the initialization, meaning that the altitude at startup need not be set precisely.
Optional 3 star init for more precise pointing.
Analysis of initializations including calculation of 3 major mount errors: axis misalignment and optical vs mechanical axis misalignment in horizon and elevation.
Pointing errors corrected for the 3 major mount errors.
Pointint error corrections for altitude vs azimuth (rocker base levelness), called ALTAZTEC, and altitude vs altitude, called ALTALTEC (tube droop and altitude bearing eccentricity)
Pointing Model Corrections (PMC) for remaining errors, achieving under 1 arcminute RMS error over 100 to 200 degree goto slews.
For stepper motors, QuarterStep Corrections (QSC) fixes physical variations in stepper motor movement from quarterstep to quarterstep.
Powered field de-rotation with slew using either the SAA1042 or the ECG1857 or the MC3479 bipolar stepper driver chip on the stepper side, and a servo motor on the servo side..
Focusing control either by a MC3470 bipolar stepper driver chip or a DC motor by relays on the stepper side, and by a servo motor on the servo side.
Backlash compensation in both axis.
Periodic error correction of unlimited length of both axis simultaneously with on the fly PE recording, averaging, analysis, and incorporation.
Recording of multiple cycles of guiding corrections for later analysis.
Goto computerized finding from a number of contributed data files (about 100 data files now), or from manual entry of coordinates including offsets. Here is a note from a user: " One down side to your system is that I have just about exhausted new targets in a large portion of the sky. I'm working off a database of ~11,800 objects and last I checked, I've viewed over 70% of them!"
Tight integration with Project Pluto's DOS and Win95 versions, along with Allstar.
Receives LX200 protocol commands from an external PC running any of the popular planetarium programs.
Drift compensation, to track at lunar and solar rates, to follow fast moving comets, and auto generation of drift rates to null tracking.
Altitude and azimuth software motion limits.
Recovery of last position and last orientation to the sky.
Move to a home position for blind storage.
Optional external encoders so that the scope can keep track of its position when moving by hand, including option to use the mouse encoders.
Real time display of all coordinates and status.
Robotic scrolling motions, best described as high magnification 'fly-overs'.
Enhancement of scrolling actions so that initializations and analysis can be done automatically, and, object coordinates can automatically be pulled from data files.
Grand tour, where a flip of a switch takes you from object to object in a data file.
Wireless mouse operation at the eyepiece, so no handpaddle cables or motorized focuser cables.
Ability to record scope position from the eyepiece, for later use in data files.
A number of test options to test telescope, encoders, motors, hardware, and software.
Because software is PC based, improvements and changes per user requests can be made quickly, sometimes that afternoon in time for the next night's viewing.
The disadvantage of this system is that you need a PC or laptop. However, you can buy used pentium machines for as little as $100 and laptops for $25 to $400.