Posts Made By: Michael Mills

I would like to know the specifications for the little spur gear inside the SP-C6's sliding focuser. Our club's SP-C6 loaner scope has been missing its focus knob and gear for a long time, and I can't find a replacement anywhere (Vixen NA wants a lot of money for a replacement focuser). I am going to try to fabricate one, but it would help if I could get the gear's dimensions, rather than relying solely on my measurements of the rack gear and bushing.

Thanks,

Michael Mills

Looks like a draw latch. Try McMaster-Carr to start (www.mcmaster.com). Search for "draw latch" or "lift and turn draw latch".

-Mike Mills

I recently had the opportunity to examine and test a friend's new Obsidian 16" f/4.5. I was impressed by the quality of the polish--there was absolutely no scatter from a green laser pointer shined on the surface. The figure was also very smooth and the edge looked perfect. My Foucault results differed slightly from the maker's in the central zone, but still showed a very well corrected figure--something like 0.96 or 0.97 Strehl ratio (I don't have the numbers in front of me). I would say Obsidian is making very good optics, although it took them about a year to deliver that mirror.

Cheers,

Michael Mills

Lee Valley Tools has a good selection of knobs. See http://www.leevalley.com/hardware/page.aspx?c=2&cat=3,43576&p=52800 .

I don't know if any of the bolts on the male knobs are 2" long. If not, then you could use JB Weld or Loctite to fix a piece of 1/4-20 all-thread (of any length you like) in a female knob.

Good luck,

Michael Mills