How do I figure out star rotation from a series of photos?

Question

I have a large series (~1000) of wide-angle photos, taken with a medium quality digital camera over a period of 2 hours. I'd like to automatically figure out the rotation speed and center of rotation (north star), and using that info and the photo's EXIF timestamps, stack all the photos into a single, simulated long exposure photo like the pros do with their fancy motorized telescopes.

I've tried StarStaX , but while that does nice median calculations and creates pretty star-trail photos, it doesn't do alignment. Hugin's cpfind is better at real-world control point detection, and dies when trying to pinpoint star location.

I think I can do a pretty good job of identifying stars using local brightest points, but I don't remember enough freshman math to take the ~500 vectors aligning the stars between two images and boil that down to a center of rotation and a theta.

Any suggestions? Image stabilization code?

Answer 1

Can you post link to 2-3 samples of your star photos? I guess optical flow calculation and then affine transformation (rotation and possible shift) search for this flow will help.