Polar Alignment issue

[Robertjohn]

I've successfully used the package's Polar Alignment routine in the past and have achieved 'Good' using my HEQ5 (although I'm a fairly recent convert and don't get my rig out as often as some). I tried to find this issue in the existing PA stream but couldn't so decided to post - my apologies if this has come up before.
I tried to use it recently, but to no avail. It managed to plate-solve the region around Polaris but it failed to plate-solve after I rotated in RA for stage 2 of the process even though the number of stars identified cleared the minimum required.
I tried again the following evening and successfully got to the "Up 40', Left 1°" bit in stage 2. However, at about the Left 20' point I got a message saying "please undo rotation". I followed the instructions and it duly kicked into life again, but as soon as I got somewhere near that 20' point ... you guessed it!
I even restarted the whole process twice and got the same result, rotating in RA by ~70° and by ~90° (East, as I was concerned I might hit the edge of a tree if I rotated West). I spent over an hour trying to work this through before I gave up.
Anyone know what the reason/solution is?
(The folk on my two local Amateur Astro society Facebook groups could only suggest I switch to using a drift method or the routine in NINA, but there's got to be a SharpCap solution to this surely.)

[admin]

Hi,

from the sound of things you are having problems where SharpCap is only managing to plate sovle the pattern of stars in the image rather infrequently, and is possibly even getting incorrect results from the plate solving calculation at times. This would account for sometimes not being able to proceed and also the 'undo rotation' message, which appears if SharpCap thinks you have made an additional rotation after moving to the last adjustment stage (the threshold is deteting a 5 degree rotation.

If that is the case then you will often see the 'Could not solve' status showing in the polar alignment area, meaning that SharpCap is not able to calculate the position of each frame from the camera. There are lots of hints on how to solve this problem here in the polar alignment troubleshooting guide : https://docs.sharpcap.co.uk/4.0/#Troubl ... 0Alignment

In particular try increasing exposure and gain a bit and do make sure that you are within 5 or 6 degrees of the pole in your starting position.

Hope this helps.

Robin

[Robertjohn]

Thanks Robin, I will certainly try again (weather etc. permitting) before going down the expensive dedicated PA camera route. I have read the help file, and watched a YouTube recording of a talk you gave on using the routine. Exposure times (2s) and gain were both high enough for it to tell me ~30 stars were detected. It struck me as odd that I'd used it successfully a couple of times before this evening of repeated failure. However, as per my opening, I am content to try again given that there's evidently nothing horrendously amiss with my method.