Most people on this forum will not have access to a driven mount but may still want to have a go at some astrophotography. One of the easiest things to take is of the night sky using a fixed tripod and do a long time exposure. Attached is a 15 minute exposure with the camera pointing towards the pole star and you will immediately notice that sky glow can be a real problem. To some extent it can be improved in photoshop as in the second picture. However I have just come across (via an OU forum) a piece of free software that enable you to effectively take a long exposure without the sky glow. You instead take a large number of 30s exposures and stack them. The program will do that for you by just giving it a list of images. The sofware is available at
http://www.startrails.de
As far as I can see any camera can be used but an advantage of a DSLR is that it can be set on multiple exposures and a remote lead set on continuous and the camera will keep on doing 30s (or whatever the longest automatic time is on the camera) until it is disabled. A two hour set would produce some interesting pictures. The trick then is to have an interesting forground.
It would be worth having the iso set high e.g. 800 iso if available but will work on lower.
By the way, the dust on my sensor has since been removed.
Dave