The Swarovski TLS-800 is an 800mm SLR Camera Adapter that can be used on any of the AT-80, ST-80, ATS-65, STS-65, ATS-80 & STS-80 spotting scopes, as well as the CT-75 & CT-85 collapsing telescopes. The focal length does not change with the device being used, but the aperture does. It requires a camera-specific T-mount adapter.
Although this adapter can be used with the CT series of collapsing telescopes, it is a bit annoying in use. Since the entire barrel of the CT series will rotate when focusing, the camera will rotate as well, making it necessary to repeatedly loosen the set screw upon the camera adapter so that the orientation of the camera is properly vertical or horizontal. But it does take a fine photograph, so if you are determined to use your CT scope for picture-taking then this is the only way that can be achieved.
Ultratelephoto photography is easily achieved with your spotting scope and the TLS-800. Take precautions to minimize vibrations, such as locking up the mirror if possible and using a cable release or remote control to fire the shutter.
First, remove the eyepiece. Next, attach the SLR camera adapter where the eyepiece would normally be attached to the spotting scope, and screw in a t-mount adapter to the opposite end of the SLR camera adapter. Now you can attach your camera to the t-mount and you are ready to begin taking pictures!