Telescope RA Drive Corrector
I built this drive controller back in 1990 for my orange tube C-8, which had a synchronous AC RA drive motor. It was also used with my Ultima-8 until I upgraded its RA drive to a servo motor. Now it will be the drive controller for my Questar 3.5, so it still hasn't outlived its usefullness.
The heart of this controller is a Vogel Enterprise VE Digitrack controller PCB. Vogel sold complete controllers or just the board for building your own. It has crystal-controlled Siderial, Solar and Lunar drive rates.
This AC drive controller converts 12VDC to 120VAC at approximately 60Hz, The exact frequency is set by selecting one of the programmed drive rates. The two RA buttons on the hand paddle are then used to vary the selected drive rate as needed to keep an object in the eyepiece field of view. One button increases the frequency slightly, speeding up the synchronous motor, and the other momentarily stops the motor, slowing down the drive.
The heart of this controller is a Vogel Enterprise VE Digitrack controller PCB. Vogel sold complete controllers or just the board for building your own. It has crystal-controlled Siderial, Solar and Lunar drive rates.
This AC drive controller converts 12VDC to 120VAC at approximately 60Hz, The exact frequency is set by selecting one of the programmed drive rates. The two RA buttons on the hand paddle are then used to vary the selected drive rate as needed to keep an object in the eyepiece field of view. One button increases the frequency slightly, speeding up the synchronous motor, and the other momentarily stops the motor, slowing down the drive.
In the front is the drive rate control and a momentary toggle switch to tweak the RA speed. It also has a momentary toggle switch for controlling a simple DC Declination motor.
In the rear are the jacks for connecting the controller to the scope. There is a jack for a hand controller for more conveniently making RA and DEC adjustments while peering through the eyepiece. There is also a jack with a brightness control for an LED-illuminated reticle. And, if the ST-4 port is not being used, there is a looping plug installed (when I built this I owned (and still do) an SBIG ST-4 Autoguider).
A look inside at the Digitrack PCB. The controller is in need of a little work inside and out. One switch needs replaced and some of the wiring needs cleaned up. And all the old panel labels need replaced.
Page created 3/19/2020
Last edited 3/24/2020
Last edited 3/24/2020
