[bojan]

Over weekend I did some testing again, and confirmed there is some astigmatism See attached image).. so I opened the lens today.. the main mirror retaining ring is glued to the frame and most likely over tightened..

I tried with acetone, but couldn't turn it (using the caliper as a tool..).
I think I will have to make a proper tool to do this job and/or apply more acetone to soften the glue enough so I can free the glass from the tube.


EDIT:
Success! more acetone definitely helped. Now, star test again.