I have two images taken within 30 minutes of each other in the same part of the sky. They are very similar but are slightly offset due to the Earth's rotation and other factors.
I know: the X, Y coordinates and RA/dec of the center of each image, and the pixel scale of both images (eg. 1.3 arcsec/pixel).
I've tried treating the image as though it had a linear coordinate system, but the field of view is wide enough (~12 arcmin) that this isn't really accurate.
I want to align these images so the stars overlap. How do I determine the X,Y pixel offset of these images so I can overlay them?