Dear Emile, It just so happens that a couple on months ago I was asked to help out with much the same sort of thing but on a much smaller basis (perhaps only about 50 frames). Just over a month ago I received the book by Richard Berry and James Burnell, called "Handbook of Astronomical Image Processing" (Willmann-Bell Inc) which includes a CD with some excellent software and to quote Tonny Vanmunster "This is excellent reading and a must for all CCD users!!". But not only does it reduce CCD images you can do photometry on photographs as well. There is a function which will convert just about any image into fits format whereby you can then use a function to determine all the stars in a particular frame down to a certain level to find the limiting magnitude (which is what I need to do). In addition though, once you have the image in fits format you can perform photometry on a single star, on several stars on one image, or on multiply images to obtain a light curve, for example. For more information look at http://vsnet.willbell.com/aip/index.htm. There is also an excellent e-group at http://groups.yahoo.com/group/AIP4WIN/. Let me know if I can help you further. Best wishes, Roger ----- Roger Pickard, Director, BAA Variable Star Section, 28 Appletons, Hadlow, Kent TN11 0DT. England. Tel: 01732 850663 (Int: +441732850663) E-mail: rdp@star.ukc.ac.uk BAA VSS Web Page: www.telf-ast.demon.co.uk/