Tele Vue manufactures auxiliary lenses which significantly improve the quality of photographs you'll get with your telescope when used with a T-mount and 35mm or digital SLR camera.
The TRF-2008 0.8X Reducer converts the focal length and aperture of Tele Vue's TV-85 to a 480mm f/5.6 and the Pronto to 380mm f/5.4-but can be used with most 350-600mm refractors which have a 2" focuser. Enjoy flat field, fast photography with managable exposures!
The TRF-2008 inserts directly into the optical path of 2" focusers and has T-threads upon it so that you just add your camera's specific T-mount SLR adapter adapter.