Thank you Neill for your speedy reply to my incomplete question!
My problem as a novice in digiscoping despite being a seasoned photographer directs me to a few more words.
I get constantly blurred shots with my P6000 mounted on the ATM80 by a UR-E21, a step down ring 43-37 on the DCA backplate M37. A bit more than 3 mm are in this way added and I suspect that being the root of my problems.
I therefore thought that maybe a backplate 43 mm going straight into UR-E21, would ease my problems. Next comes of course my total inexperiense with the scope. I have therefore tested all available guides and advices for the P, S, A, AF setting, ISO and of course the speed, plus whatever crossed my road.
I'm not giving up, but continue. Though, for my continued mental balance I just bought a Sony NEX5 with the 18-200 mm zoom, which has already given me great pleasure when working directly with it and giving the scope a rest.
One small point more: Swarovski is advising to use the backplate M28 for the P6000. However, that brings my P6000 into a red flashing coma when passing the centerpoint between W and T. Obviously because the lens then is brought into physical contact with the DCA backplate. Hence, my use of the M37 and corresponding result, by now a rich collection of step-down and -uprings.
Finally, thank your for your many enlightening articles, responses and photos!
Erik
PS, YES, I do possess an M52 backplate for the DCA