50mm Tube Rings

[steppenwolf]

I have an old (cheap!) 500mm telephoto lens that I want to use as a guide 'scope but I need to mount it firmly so I am looking for some 50mm inside diameter tube rings at a sensible price! Any thoughts on where I might get some?

[beamer3.6m]

You could get 90mm tube rings and then drill them.

In the 3 drilled holes, set 120 degrees apart, insert 3 screws. This way the screws hold the scope and allow you to direct it to a suitable guide star.

[Kaptain Klevtsov]

Something like this?

(click to enlarge)

Kaptain Klevtsov

[beamer3.6m]

A picture speaks a thousands words.

[steppenwolf]

Thanks KK and Beamer3.6m - I have already made my own collimating rings in this manner for a larger 80mm diameter 'scope but I guess that longer bolts would do just fine on the smaller diameter of the 50mm diameter telephoto lens.

[beamer3.6m]

Yep.