Has anyone used the QHY Polemaster as a camera for polar alignment in Ekos instead of the main camera or guide camera and does that work?
Reason for asking is that I compared the alignment error using the polar alignment module with my polar scope the other night. I took great care of aligning my mount using the polar scope and verified perfect (+/- 1 arc min) alignment by rotating the mount around the RA axis while watching Polaris draw a perfect circle along the line it is supposed to be on in my polar scope. I estimate the intrinsic error of that method to be +/- 1 arc min based on the reticle markings. I then determined the alignment error using the polar alignment module and my main telescope (ES102 - FL 714 mm). According to that, I was 5 arcmin out of alignment.
I suspect that the discrepancy comes from flexure of the OTA. I therefore would prefer to use the Polemaster, which is mounted directly on the RA axis and would not be subject to flexure.
Note that I usually align exclusively using a polar scope and I have had absolutely no problem so far with exposures up to 7 min. Pinpoint stars every time. But I have a smaller travel mount and that is not nearly that accurate, so I am looking for a simple alternative that works on a Pi3 and for which I do not have to lug an extra Windows computer around with me.