This happened on the first frame of a series. Any ideas? The only thing I can figure is the image started before the slew and before the rotation finished. And only one of the stars was bright enough to leave a trail. Doesn't fit exactly, but is only thing I can come up with. https://www.dropbox.com/s/m9v7j7up8sbcuqe/IC 417 H -25C 1800 BIN1 PA064 E 20170106 20170106 192955.fts?dl=0
I think you are right about the rotation. I see a second faint circle around the bright star upper right as well. Robert
Do you have a rotator? It sure looks like it was rotating while the shutter was open. That line is a trail from a bright star.
I can't see the 2nd circle for the life of me, but my imaging partner sees it too. A very strange situation indeed...
Yep...have a rotator. Can't imagine why ACP would start an exposure before rotation was completed. It calibrates away and only happened this one time.
It must have been a glitch, either hardware or software. I'd suggest (a) checking your logs, and (b) keeping an eye to see if it happens again. In any case - not a camera issue for sure.