converting Sigma 600/8 mirror lens to spotter

I just realized that the old, barely used, Sigma 600 mm f8 catadioptric mirror lens potentially might be usable as a spotting scope, IF I could find a source for an adapter that would convert a Nikon bayonet mount, to something that would take a 1.25" mirror or prism diagonal. Coupled with a Meade 18 mm SWA telescope ocular, that would give me a 33X scope with a 2 degree field. It wouldn't be weather proof, but we get very little rain here in Central California 8 months out of the year.

Can anyone recall a potential source for such an adaptor? Thanks

Alan, about 20 years ago I bought something that turned a telephoto lens into a spotting scope. I think it came with a built in eyepiece (10mm?) and possibly an erecting prism assembly. But, it didn't perform well enough for me to use it. Here's what I would suggest:

Bore a hole through a rear lens cap, and glue or otherwise mount a plumbing flange/pipe with 1.25" ID.

Let us know what you decide/do. Contrast might be low. Good luck,

-- William Chang, Saratoga CA