Hello everyone,I'm new to this forum and relatively new to the practice of photographing("imaging")the night sky.Since I don't yet have a telescope I'm limited to wide-field shots from a tripod using a canon a80 powershot digital camera.One project I could do with my current equipment ,that I think might be kind of neat is to image the constellation ursa minor at regular intervals from dusk to dawn,and then create a composite image of its rotation about the celestial pole.I've accomplished the first part as i've captured a number of satisfactory shots taken at ~1 hour intervals on consecutive clear nights(rare in these parts).My question is :how do I create a composite image(ie. showing the dipper at 9pm,midnight,3am and 6 am ).I do have access to several image processing programs(paint shop pro,GIMP)as well as some specialised astrophotography programs(registax,registar,stellar magic).So what I'm looking for is any pointers as to which program might be best for my project ,and also any specific tips within a given program.I apologize in advance.if this post is long-winded,but ANY ideas are welcome .and would be greatly appreciated.Thanks.

registar, stellar magic, paint shop pro, photoshop, registax..they are all good

It really depends on what program you find best, and which one you'll find the easiest to use and most helpful for what you want to do, and most suited to your own unique camera shots