Hi, and thanks to the OP for this thread.
I have a first version 15028HNT Sharpstar, with the very loose primary. My original solution was I inserted shims of ptfe that I had that was the correct thickness to take up the slop between the mirror sides and the cell. This seemed to work fairly well. However, I never liked the mirror cell in the first place so I decided to go with a different, although more expensive and drastic solution. I replaced the cell with one from https://www.aurorap.com/ It took a bit of modification to the scope end ring to get it to fit but the end result is a much more robust cell. Pics attached. After reading your modifications, I will make an apature mask. Then I think I will have a very nice end result
Che
