I spent some time shooting M31 the other morning. I got 16 good frames before my mount turned off (another story, since solved). I stacked those in DSS and here is a link to the uncropped result. It's not much, but it's a start. One thing I noticed right away is the stars on the right side of the image are elongated whereas on the left they are pretty much spot on.
My PA was dead accurate.
I am using the AT60ED with a 0.8x flattener/reducer and the ASI183MC Pro. The mount is a star adventurer 2i.
Exposure info: 16 x 30", gain 111 (unity), temp -10c
So I'm convinced its not a PA error, because star trailing would be present everywhere if it were. I'm confused as to why I'm seeing elongation at all because I've been told with the small sensor size on the 183MC I don't need the flattener at all.
So is this a tilt issue? If so, how do I fix that? I don't have a tilt adjustment on the 183.