I have an a Celestron 80 mm f/5 with Losmandy rings. The spacing is only 4 1/2 inches and the alignment does not hold. I am thinking that a longer distance between the rings will work better. Thanks for the question Ken Sikes ----- Original Message ----- From: "Jim Waters" <james.t.waters@xxxxxxx> To: <az-observing@xxxxxxxxxxxxx> Sent: Tuesday, September 02, 2014 5:55 PM Subject: [AZ-Observing] Re: Orion ED 80 f/7.5 Why are you considering this scope? The Orion Short-Tube 80 (F/5)will work. The f/7.5 is about 2 feet long. Jim -----Original Message----- From: KenGSikes Sent: Tuesday, September 02, 2014 5:21 PM To: SAC Mail List ; EVAC ; AZ Observing List Subject: [AZ-Observing] Orion ED 80 f/7.5 Has anyone had any experience using the Orion ED 80 f/7.5 as a guide scope on a 10" SCT ? Any advise would be welcome Ken Sikes -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list. -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list. -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.