Tele Vue Optics 400-600mm 0.8x Reducer/Flattener:

Model TRF-2008

Key Features:

Optimized for TV-85 and TV-76: Transform your TV-85 to 480mm f/5.6 and TV-76 to 380mm f/5.0, perfect for efficient and flat-field photography.
Versatile Compatibility: Suitable for use with any 400-600mm doublet refractor telescopes, broadening your astrophotography possibilities.
High-Quality Optics: Features a fully multi-coated, 3-element design ensuring excellent light transmission and clarity.
48mm Filter Thread: Integrates a 48mm filter thread for easy attachment of standard filters, enhancing your imaging capabilities.
Direct 2" Focuser Insertion: Designed for direct insertion into a 2" focuser, ensuring a secure and stable connection.
Standard T-Ring Compatibility: Accepts standard T-Rings for 35mm cameras, making it compatible with a wide range of DSLRs and mirrorless cameras.
Recommended Spacing for Optimal Performance: Use a spacing of 56mm +/-2mm between the top TRF-2008 flange and the image sensor for peak results.
Sky & Telescope Acclaim: Praised in a review by Sky & Telescope in July 1999 as a "must-have" for TV-85 photographic use.
Ease of Use: Straightforward and user-friendly, ideal for both amateur and professional astrophotographers.
Enhanced Astrophotography: Significantly improves your astrophotography experience by providing a faster system and flatter field.