I've been away all weekend, but I had calculated that the terminator was crossing Plato this morning and I still have not properly seen the small craters within its walls. So I said I must give it a go.
Went to bed with cloudy skies. Got up at 3:30 and - only scattered cloud and nice bright Moon fairly well positioned. Had the Turbo Starcatcher set up in the driveway and collimated in 15 min. All rugged up against the cold - started looking.
Yes, terminator was nicely placed on Plato BUT the seeing was shocking! Couldn't get stars to points; the Moon was a jelly and Jupiter a fuzzball with only hints of the major band.
Persisted for half an hour, saw some interesting (low resolution only) features on the Moon, eg. the sunlit tip of the central peak in Eratostheses, then it clouded over, so I packed up and was back in bed by 5.
Edit - had a thought. I wonder if my mirror was a bit too warm. I noted it was at 11 deg when I took it out from its storage location. When I put it away about an hour later, outside temp was 3 deg and the mirror was down to 7 deg?