Arp, Steller Magic was one I found that could do RGB recombining. But I could not work out how to do the Offsets that Mike discusses in his article.
Also when you say Saturn is in diffrent position do you mean that your camera has rotated? Or that it is not in the centre of the frame? If frame centre then PPMCentre could do this for you. Mike mentions this in his article
http://www.iceinspace.com.au/index.p...63,306,0,0,1,0
Regards
Fahim