Chuck wrote:

I may still actually have the original instructions. If so, I will make a copy for the Ealing manual.

Thanks. I'm sure the club members would appreciate it. After practing calibrating the controller again last night, I have made a small revision to my use notes. On both the initial rough and the later final calibration, the calibration light should be adjusted to make it go out - not hold steady. Lurkers, please disregard and replace the prior cheat sheet. The good news with calibration, the drift rate without periodic error correction (PEC) on the 40 year old mount meets the performance of a Vixen mount without PEC. - Peace Kurt ======================= Use notes on the Ealing for lurkers With drive calibration, the Skywizard still registers an index error of about 0.3 degs in RA only for a 9 deg slew on two tests (Vega to M57 and Vega to M13). That means at best the Skywizard will put a target somewhere in the Mak view, but it cannot be used for actually getting the target into a short-focal length (32-25mm) observing eyepiece. CHEAT SHEET FOR CALIBRATING THE EALING'S ASTROPHYSICS MODEL 8002 DRIVE CONTROLLER The controller uses a quartz crystal to generate a reference signal. Knobs and lights on the front of the controller, left to right, are: Calibration Light Power Mode - Sidereal, Solar, Lunar, Calibrate Calibration Knob - This is non-functioning. Set it to the middle and forget it Auto-Manual RA - Always set to manual Auto-Manual Dec - Always set to manual Plug-input for the slow motion control and also off to the side - Separate slow motion control with rate dial knob. Procedure: 1) On start-up, set the Mode to "Calibrate". 2) The Calibration Light will slowly flicker over 0.5 to 2 seconds. 3) Using the dial knob on slow motion control, turn the knob until the rate of flicker in the calibration light is minimized. Typically, it will flicker over 2-5 seconds. On start-up the crystal is cold and you will not be able to absolutely calibrate the drive rate. You can only do a rough calibration. 4) Turn the mode knob to the desired use mode, e.g. - "sidereal" or "lunar". 5) After using the scope for 30-45 minutes, the reference-signal crystal will reach operating temperature. 5) Repeat steps 1-4. This time you will be able to adjust the calibration light so it will stop flickering completely. The calibration light will adjust so it goes out. When you switch to use mode, the light will glow steady. 6) Avoid turning the dial rate knob when using the slow motion controller. I bumped it while in the middle of imaging, accidentially changed the setting, and M13 zipped right off the camera chip. Once calibrated, the drift rate for commonly observed objects will effectively disappear and the sub-arcsec drift error rate is in a zone sufficient for astrophotography. Once calibrated, the "lunar" mode also does a fair job of lunar target tracking. In lunar mode, the Ealing will track well within any limitations needed for imaging and stacking lunar images within Registax. Without drive controller calibration, DSO will drift out of an Ealing 32mm-25mm observing eyepiece in two to three minutes. ===============