Originally Posted by CIVMatt

It's a little more difficult with digital, to do it right you don't use bulb setting for long periods of time, your camera will heat up too much and start getting hot pixels on your image and it'll turn out crappy. The key with digital is to take several timed photos and merge them together.

Read up on this I found for you.

http://digital-photography-school.co...cking-software