It seems I am having trouble focusing. Attached is a frame that I took before a session a couple of weeks ago, Backyard EOS + Bathinov mask. It looks to me was OK then. Maybe I am losing focus as time go bye, during a given session.
As always, suggestions and comments are very, very welcome.
You diffraction pattern is offset to the left slightly. It should be centred. I admit its not much of an offset but it could make a difference. Also, was your equipment at ambient temperture? Focus can change due to temperature. Some camera control software can run auto focus routines on filter changes, or after so many subs, provided you have a motorised focuser. I don't use motorised focuser, but my gear is in an observatory and i usually check with the Bah Mask before i start a run. And filters should be parfocal if your using them.