Hello all,   I just wanted to share something that I recently found out and it has worked for me like a treat! I have a Sky-Watcher 72ED and the Field Flattener for it. I had to purchase a "special" adapter ring for my DSLR which is actually a Canon Bayonet adapter but instead of a standard T2 threads, it comes with M48 (2") threads so it will fit to the Field Flattener's M48 thread. I have a fully screwed imaging train which makes it challenging for framing objects properly.