TeleVue TRF-2008 0.8x Reducer / Flattener for TV-85, TV-76 and Other 400-600mm Focal Length Refractors
TeleVue TRF-2008 0.8x Reducer/Flattener for TV-85, TV-76 and Other 400-600mm Refractors
Model TRF-2008 0.8x Reducer/Flattener converts TV-85 to 480mm f/5.6 and TV-76 to 380mm f/5.0 for flat field, fast photography.
Fully multi-coated 3-element unit with 48mm filter thread inserts directly into 2" focuser, accepts standard T-rings for 35mm cameras.
"This accessory is a must-have for someone planning to use the TV-85 photographically" - review in Sky & Telescope, July 1999.
Also it can be used with any 400-600mm refractor telescope.
Important Note: This product was designed for an optimum 55mm back focus. (Distance from flange surface to film or CCD plane). If you use a CCD, be sure the spacing between flange and CCD is 56mm +/-2mm for best results.
Excerpt from review of TRF-2008 0.8x Reducer/Flattener in Sky & Telescope magazine:
"The 0.8x Reducer/Flattener performs superbly. Star images are perfectly round to the very corners of the field, and there is minimal vignetting. A high-magnification examination of the images reveals little, if any, secondary color even at the edge of the field."— Cook, C. "Test Report: Less Magnification for Photography". Sky & Telescope (July 1999). Click here for the Full Review.