Its been a while since I’ve posted on here, but I’m at my wits end. I’ve been imaging with an Orion ED80T CF on an Atlas EQ-G for about a year and a half, first with a Canon T6 and, for about the last year, a ZWO ASI178MM-C with LRGB and Ha filters. I love the setup and have been really happy with the results I’ve gotten. And I routinely guide around 0.6” total RMS, so life has been really easy as far as tracking goes.
However, over the last few months, I’ve been getting drift while imaging. Sometimes it’s really bad, other times it’s only noticeable when pixel peeping. My guide graph looks great, but there will be a consistent drift in either RA or DEC, or sometimes both. From reading other threads, this sounds like differential flexure between my imaging train and my 50mm guidescope that sits in the finder scope shoe. I’ve tried tightening everything down to eliminate it, including using pliers to tighten the thumb screw that secures the guidescope, tightening the screws that hold the shoe to the OTA, and putting masking tape around my field flattener to make sure it wasn’t slipping in the focuser. At least I’ve got the issue solved where the imaging train would slip out half a millimeter during the night, which has happened sometimes in the past. But nothing I’ve done has completely eliminated the drifting field!!!! It’s really frustrating. Usually it’s around half a pixel per minute in a consistent direction. At my image scale, that’s about .65” per minute.
I called one of the major American telescope distributors to seek advice about maybe purchasing an off-axis guider. The guy I talked to thought it was ridiculous that an 80mm would need an OAG, and said he had never heard of such a thing. He urged me to keep trying other things...that there must be something loose.
Is there anything else I can try? Do you know anyone that uses an OAG with an 80mm refractor?
I really appreciate any ideas you might have.
Edited by Thundermoon1994, 22 March 2019 - 11:50 PM.