Thank you Mike and Trish for sharing your solution - it sounds interesting and surely is a good and cheaper alternative to changing the focuser.
Greg - I'm generally happy with the focuser's performance, but as I recently looked into it more carefully, I noticed that while everything is threaded in, star shapes slightly vary depending on the telescope's orientation, that's why I suspect it is the focuser.
And then I look at
images taken by professionals, and I really stop worrying about slight imperfections and just enjoy imaging
