Hi!
I have been shooting with a Nikkor f2.8 lens 180mm on an SBIG 8300M camera. For a while I though that I was not properly polar aligned since I was getting non-circular star shapes on my images. (No guiding in Dec but guiding in RA). I took a deep-dive into this and what I discover is that the star distortions are the same independent of exposure time (up to a certain length, of course, when DEC errors come into play). So I believe these distortions are a function of my lens. Oddly, the stars are not circular in the center of view, but tend to be centered on other parts of the image (i.e. lower left corner). T
Anyway, what I was wondering is if there is some sort of function in Pixinsight that I could apply to the final image to overcome these distortions. It seems they should be able to be modeled and then a corrective function applied to overcome. Sounds maybe like deconvolution, but not sure if that is the correct mathematical function to correct for this issue.
I will attach an image once I figure out how to do that. When I post, one will notice that the lower left of the image, the stars are generally nice and round and they go down hill from there on other parts of the image. This is only a 10 second exposure, so I don't think RA and DEC errors are all that relevant as I was tracking in RA.
Thank you!
-Jeff
