I know this has been done numerous times and my end result is no where near the last few posts on here but I managed this with the astrotrac since I do not have a permanent base/observatory to image from. It was cold and foggy and I was limited to only 30 second subs and 300mm FL but I think it turned out ok considering.
Not too sure of the best way to resize the files to upload them here but it is also on my flickr (
https://www.flickr.com/photos/christianckr/15065775266/)
Thanks for looking!