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Hi Matt
Hmm, interesting? From memory, winding the focuser clockwise (CW) is required for close focusing, and C-CW for focusing at infinity?
If that is so, we must be “pulling” the main mirror towards the back of the OTA when focusing on close by terrestrial objects?
I wonder if a physical object some how cuts into the light cone as you approach the point of closest focus? This would appear as an “indentation” in the circular diffraction rings.
I’ve ordered some flocking paper from the US so when it arrives, I’ll be sure to photograph the innards of the C9.25 as I take it apart to flock it. This might reveal something?
Cheers
Dennis
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