My first attempt at the Andromeda Galaxy (Canon EOS 20D at prime focus, single 20 second exposure.) I stacked eight such photos with Registax but didn't see any improvement. Doesn't look like the Andromeda Galaxy I see in everyone else's pictures, but I'll keep working it. Seeing conditions were not very optimal as it was getting cold and hazy; and there was a lot of reflected light in the air. It will take extremely good seeing conditions and a lot more than 8 stacked images. :)