Question for Houston Astronomical Society and anyone else on the Internet

https://www.facebook.com/groups/AstronomyHouston

Can you suggest a program to take two images from different cameras, combine and compare them? I am too tired to write more programs. Just wanted to look at some pictures I found on the web and see how the fit together. They are the same part of the sky, but different rotations, different color balance, different pixels per degree. I can probably do it from first principles, but just wanted to play with the images, not more work. Many years ago, I remember overlaying maps onto satellite images. I am using Linux now.

Open one image and make it transparent. Open the second image too. Mark corresponding points in the two images. Map them one onto the other with rotation, translation and scaling. Adjust the color mapping. Find color control points, Select them and recalculate, Zoom and pick new control points. Recalculate. Continue. I think this is what some people are doing, but I cannot tell. Writing it out like this, maybe I will just write a program. Images are more fun than programming some times. But not if the tools won’t do what you want, have learning times that run into years, or that are so expensive you conclude why even bother?

If I play with some manual overlays, even if I cannot use it for what I want to do, my visual memory will improve and clarify the algorithms I need to do it right. I am getting old. I have to see examples now, I can’t do it all in my head. And the range of things I have seen in my life that I memorized, is far smaller than the universe that is presented to us now with so many more cameras and sources and people all contributing new things.