I'm not sure what you mean by a Zeiss tele lens - monocular...
Do you mean you want to put a sports optics, such as a spotting scope, onto an SLR?
If so, Zeiss make an adaptor for this very pupose which fits their spotting scopes and takes T2 adaptors so as to match up to the SLR.
I have a Zeiss spotting scope and intend to do this one day, but the adaptor is NOT cheap!
Altenatively you can use the SLR with it's standard lens to look through the scopes eyepiece by mounting it on a bracket such as are used for 'digiscoping'. Being able to fill the frame without vignetting is likely to be a problem, though. Usually needs a lot of fiddling and adjusting to line it all up. Can be a good way to take a one off picture that needs a long focal length, like a lunar picture, but not very practical for daily use!
Be aware, though, whilst these are ways to get a cheap long focus lens (well, the spotting scope is not at all cheap, but it is cheaper than buying a photo optic as well!) don't expect the flat field and even illumination you would expect from a photographic optic, the rules for telecopes are not the same...
Steve