This is my first attempt at autoguiding using such a long focal length. Camera used is a Canon 1Ds, full 35mm format. Autoguided by an SBIG 237 attached to a cheapo Makinon 500mm/8 mirror lens that had an earlier life on a Konica Autoreflex camera. Don't throw away lousy old lenses, you never know what fresh uses you'll find for them! Mount used is a Celestron CGE. This exercise was meant primarily to learn the ropes for autoguiding. If I can achieve semi-decent results at 4000mm, then serious attempts at between 600mm and 1200mm using my preferred imaging 6" APO refractor (actually a Canon 600mm/4L IS lens) should be fun. For more stuff peruse my primary website at: http://www.samirkharusi.net/