This is a vintage drive corrector for the original orange tube Celestron C8 SCT telescope. The label on the back shows it was made by Gieseler Electronics in Santa Cruz, CA (pre-Orion Telescopes). The input is either 120 VAC or 12-14 VDC, and the output is an AC voltage for driving the AC synchronous motors in the base of the C8. The frequency of the AC voltage can be varied to keep the clock drive precisely on target. It has a remote box labelled 'OmniGuide' that has a rotary knob for changing the frequency and also has a joystick for larger changes in frequency to move or center the object in view. The OmniGuide box has a 'Fastrack' switch on the bottom for even larger changes in frequency when the joystick is moved.
The joystick also controls a DC declination motor (included, 2nd picture). The motor direction with respect to the joystick can be reversed with the DEC/REV switch in the back of the main box. The Dec motor mounts on two existing mounting bolts on the side of the fork (5th picture). The 6th and 7th pictures shows what it looks like when it's mounted.
The last picture shows my test setup with the output voltage and frequency displayed on the Fluke multimeter, Here are my test results with the unit powered by 120 VAC:
1) Output voltage with no load: 136 VAC.2) Output voltage with C8 motors connected: 113-118 VAC. All the following results with motors connected.
3) Frequency with Main box set at Lunar and OmniGuide box rotary knob at zero: 58.27 Hz4) " " Solar " " : 60.135) " " Sidereal " " : 60.27 All the following results with Main box set at Sidereal.6) Frequency with OmniGuide box rotary knob fully counterclockwise (Max Slow): 59.437) " " " fully clockwise (Max Fast): 61.268) Frequency with joystick left: 46.26 (rotary knob at zero); Fastrack switch OFF
9) Frequency with joystick right: 74.1 (rotary knob at zero); Fastrack switch OFF10) Frequency with joystick left: 0 Hz (rotary knob at zero); Fastrack switch ON
11) Frequency with joystick right: 112.5 (rotary knob at zero); Fastrack switch ON
Summary: Only small frequency changes between Lunar, Solar, and Sidereal settings. Rotary knob increases or decreases frequency from 0 to about 1 Hz from the center position. Joystick quickly increases or decreases frequency about 15 Hz (with rotary knob at zero and Fastrack switch OFF) to move or center the object in view.
I also verified that C8 was moving as it should (the RA settings circle has 5 minute divisions and scope moved 3 divisions after 15 minutes). The only test I did with 12 VDC input was verifying the scope moved as it should.
Includes the hard-to-find cable to connect to the C8 motors. Unit can powered by 120 VAC using the included AC cord, or by 12-14 VDC using the included DC cable.
C8 and multimeter not included. Only what is shown in the first two pictures is included.
Filed under: Eyepieces & Accessories