It is possible, someone already mentioned digiscoping. I know a chap at my local wildfowl reserve who shoots with a big Leica scope (something like 2000mm in our terms) with a Y adapter which connects a Nikon D2xs and a normal eyepiece. Vignetting is a real problem but also is the need for high ISO because scopes, while fine for the human eye, don't really allow enough light for photography, therefore your results will be ok, but quite noisy. Also keeping a rig like that stable for the shot is hard too.