Tension on my reducer or....?

[Robindonne]

First night out after a cloudy week.  And i did change some adapters in the mean time to get to the required backfocus of my c8+reducer.   But what can this be?   
tension on the reducer?

Edited June 10, 2020 by Robindonne

[Robindonne]

It’s gone after removing the reducer.  I

[wimvb]

It could be a reflection. Tension (pinched optics) often shows itself as misshaped stars.

[Robindonne]

Okay.  Wel i hope it is.   The night before, when assembling the sct ring to the oag, i noticed how tough the reducer was screwed out of the oag adapter(sct-m48).   It seemed that the rotation mechanism of that oag putted some real force on the adapter, so much that unscrewing wasn’t possible.   A good thing of course if you’re worried of things getting loose, but the tension was the first thing that came up my mind.  So reflection is the possible cause of this crab-shaped star?    Ill try tonight without the oag prism.  See if it works.   Thanks