Hi all
I've just purchased a 500mm Vivitar f/8 Schmidt-Cassegrain mirror lens from Lars (a member here on the forum). It had a Pentax threaded ring mount so I adapted a Nikon bayonet mount and attached the lens to it. Luckily the internal thread on the bayonet ring matched the lens thread. So - I have a 500mm lens for the camera. They're not brilliant lenses I've heard, but at 500mm anything is going to be tricky to get to perform well.
Anyway - I went a step further and adapted a spare Nikon extension tube that I had lying around to create a mountable body for the lens, and one that could also carry my Orion illuminated reticle.
Success! The unit works very well with the reticle, so I intend to mount it on my Celestron C8 and give it a go soon. Focus is a bit critical, but once I find infinity reliably I'll be OK I guess.
Good bit of fun. Thanks Lars!
Cheers
Chris