I'm not sure exactly what you are trying to do, but I use a program called Astrostack for astrophotography (
http://www.astrostack.com/ ). If you take about 150 pictures of an object, the prog combines them to produce a single image much better than any of the originals. I think it works by "adding" parts of the image which are similar and "subtracting" parts that are different (like noise).It also aligns the images. It is better to take a few hundred digital images of an object and combine them this way than try to take a long exposure with a CCD camera as you get less problems with digital noise and it reduces the effect of poor seeing....and the demo version is free!