As I had reported earlier, I continue to have difficulties getting the guider to calibrate. Actually to such an extent that these difficulties prevented me from guiding altogether. The setup is a Losmandy G-11 with a TS107-S main scope (107/700) and Celestron C4-R guide scope (102/1000). Both scopes are equipped with ASI 294 cams and stepper motor focusers. Cable tension/flexure is not an issue as all cables are kept within a cable tube that moves in lockstep with the scopes. This setup worked flawlessly for years, calibration included.
Recentyl though I experience with what I consider "impossible" calibration results. The most recent night started with calibration via the main scope and delivered this result:
Ugh! Another try with the guide scope:
I aborted. WTF! Earlier I also had calibration attempts where the RA backward movement went exactly in a 90° angle vs the forward movement. This IMO is totally impossible to do (particularly for 10 pulses in a row, all going exactly in the same direction). So in order to SEE what my mount is actually doing I captured a video of RA and DE slews (the DE slew is not included in the video).
As you can see movement is perfect. No hint of any irregularities. So KNOWING the mount was doing exactly what it should, I immediately had another calibration attempt. Outcome:
Check out DE backward movement. Can you believe it? This may look like a loose DE axis but I double checked, it was locked firmly. The next thing I did was take another video illustrating RA forward and backward movment
utilizing guiding speed (0.5x). The video once again shows the star behaves perfectly. RA forward and backward move in parallel, same with DE forward and backward.
Right after this I again started a calibration attempt. Outcome:
At that point "candid camera" came to mind. I almost ran out of ideas what else I could try. I ended up searching for my old ST4 cable (Yes, I was desperate indeed). I found it, changed guiding from "Via: Losmandy Gemini" to "Via: ZWO ASI 294MC" and started calibrating again.