This is an area I myself want to study, and infact was planing to use photos of stars as exactly the medium to start with, But until I finish with the developem to the distort I would not even look at 'Image registration.
Give it a year or two and a different story may be given for ImageMagick, just not now. Not unless you like to do some development work with IM yourself

You are welcome to hack the code and submitt patches you know.
