This was shot through the 8 inch f/6 reflector. 10 minutes, 1600 ASA. Single frame with some curves, levels, and color balance adjustments in Photoshop. It is the full-frame from the modded Canon T3i. I actually took 6 exposures just to see if the guiding was up to snuff. And it was.
The stars are warped around the edges of the frame due to coma inherent to reflectors.
To guide this setup, I have to use an off-axis guider. Originally, I also had a Baader coma corrector (the MPCC) attached to the off-axis guider. But I was getting warped stars which was really puzzling. I was worried that it was guiding, but in fact, I finally deduced that it was the single screw on the focusing tube which was pinching the optics of the coma corrector.
I have to either switch coma correctors or get a new focusing drawtube. It's always something.
And here's a crop of an image taken earlier with the coma corrector in place:
Those slightly warped stars come up in short 10 second exposures as well. So that meant it wasn't guiding/tracking errors. When I removed the coma corrector, that elongation disappeared. Another possibility was that it was the scope optics -- luckily that wasn't the case.
[Update: Will be getting a new compression ring drawtube for the focuser. I plan to send the focuser to Moonlite Focusers for the replacement after I finish with the M101 exposures.]
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