Question from Ken: Is it possible to connect a Canon DSLR to my Swarovski 80 HD spotting scope?
There are two ways to do it:
Connect your scope to your 20D via photo-adapter & T-ring:
This will render a 800mm f/10 telephotography setup for your DSLR.
It's also possible to photograph through the eyepiece & 50mm camera lens with this adapter:
Before you go this route, you'll want to determine if your 50mm lens has a filter thread and what size it is. Supported thread sizes for the DCA are 28mm, 37mm, 43mm and 52mm. You can step-up/step-down, but distancing the camera lens from the eyepiece is generally a bad thing.
For more information: Digiscoping with a DSLR!