I'm new to AP. I'm looking at getting a oag and read that the celestron one is pretty good but I have to calculate backfocus because it's pretty long. I'd be using a C11 with a 6.3 reducer then the oag and then the asi294. Can anyone help me figure out what my backfocus would be? Or should I be looking at another oag?
Edited by Nbsdsailor, 24 May 2019 - 12:22 AM.