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I have never seen this before and the only thing I did different was the camera and possibly a higher dew heater temperature. I have never even seen stars with the slightest coma and I never use a flattener/reducer. Even when I have had poor focus in the past, I still don't get coma like this. Also like I said the next 3 images I took didn't have this problem. (possibly because the temperature had stabilized).
If you get a different result to usual then something has changed - I did the usual set-up and polar alignment etc. I checked collimation (good). I focused as usual, I had the dew temperature higher than usual and it was colder than usual.
I still suspect it has something to do with turning the dew heater on just before this image was taken. I suspect the change in temperature has affected the corrector plate.
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