Plate solving rotation error in Sequence Generator Pro

[Brett Nickeson]

Apologies if this isn't the best place to ask a question regarding the plate solver within SGP. But I am having a repeated issue where the ASTAP plate solver within SGP is able to quickly center to the correct location, but it seems to have an impossible time generating the appropriate rotation correction. This has now occurred three times with two different lenses (a 135mm camera lens twice and a 72mm f/5.6 telescope). Within SGP's plate solver, again it solves the center extremely quickly and is able to move the mount to the correct location. Then when it comes time to manually rotate the camera (I do not have an automatic rotator), the initial correction it displays is typically quite accurate. For instance, last night it said to rotate the camera 36 degrees counterclockwise. I did roughly that within a few degrees and was able to visually inspect the new plate solve image being only about 3 or 4 degrees off. However, as soon as that plate solve image actually solved, SGP now said I had to rotate it 73 degrees counterclockwise despite it being only a few degrees off. Could this be an error with ASTAP or is it more likely an error within SGP?

I just discovered a thread on SGP forums with other users having similar issues with the rotation https://forum.sequencegeneratorpro.com/t/updated-version-of-astap/17551/9 Does my issue have to do with the angle signage flip they described? FYI, this is for an un-flipped image.

[han.k]

Hi Brett,

No problem to ask here. There where some problems with the angle due to angle reporting modification by ASTAP. This should have all been clarified but are you still getting SGP updates or did you stop updating?

Anyhow this does not clarify your report, an angle of 3 or 4 going to an angle of 73. That doesn't make sense. The previous problems where all related to mirrored positions. Like an angle of 3 could result in 90-3=87 degrees.

Best would be to test more and describe what's actually happening in your setup. If that's clear you can ask SGP developers to address it. The solver does not report wrong angles. The previous SGP problem was only due to mirrored interpretation.

Han