[[1ponders] (Paul)]

I've had a Stellavue 50mm finder for quite some time now and while it has lovely optics the helical focuser has always been a bit of a problem. Firstly it has always been very stiff to focus, so much so I had to be careful focusing that I didn't throw out the finders alignment with the main scope. Secondly, even though it was stiff to focus if i left an illuminated reticule (with pulse illuminator) in it, the weight of the illuminator off to the side would gradually rotate the focuser so next time I looked it was out of focus.

Recently I decided to try the finder as a guidescope, so out came the turps and I pulled the focuser apart, cleaned it out and regreased with Supalube. Slick and smooth focusing now. Too slick and smooth now with no 'stiction' to resist gravity.

Short of getting a grub screw put in, can someone suggest a means of tensioning the helical focuser to reduce (eliminate) focus shift? I could put in a heavier grease but then i'd be back to 1st base. I have also considered a rubber O ring, at the base of the focuser but that would only solve the problem in one direction.

thanks