This is "by-catch" of my focusing test session. Shot from the terrace in Frankfurt utilizing a TS107-S (107/700), TSFlat2,5, Baader IR/UV block filter, ZWO ASI 294Pro on a Losmandy G-11. Guiding through 102/1000 refractor + ASI294MC. 66x2 minutes lights, gain 120, -10 degrees, 60 darks, 60 flats, 60 dark-flats. All lights with a HFD value of >3.3 were dismissed. I had to manually focus with a Cuzdi mask since I had ruined my motor focus during the previous night (connected the controller board to 13.8V instead of 8,4V, ran lots of focusing trials which eventually made the motor driver go up in smoke).
There was no wind and guiding was remarkably good:
Two days later I received the needed spare part and fixed the motor focus. During the following night I once again aimed at M 51. This time I managed to collect 34 light frames <= HFD 2.9. Conditions were not as good as during the previous session but the motor focus made things much more comfortable for me. Despite the increased noise level one can notice the better quality of the slightly lower HFD light frames. [Unfortunately in the scaled-down versions that I had posted you'd notice the increased noise level only so I removed them.] The photographs were stacked, stretched and slightly color boosted only. No de-noising or other tricks applied.