Astro-Physics CCD Telecompressor for SBIG CCD Cameras (.76).
Clear aperture is 1.75". Compression ratio is 0.67x with SBIG ST7/8/10 + Color Filter Wheel installed, 0.75x without the Color Filter Wheel. Suitable for telescopes with focal lengths of f7 to f18 including Maksutov-Cassegrains, Schmidt-Cassegrains, Ritchey-Cretiens, and refractors.
Originally developed to tame the focal length the Astro-Physics 10" F14.6 Mak-Cass, this telecompressor will provide full coverage of the ST10E chip with scopes ranging from F9 to F18 focal ratio. The 2-element cemented design transmits close to 99% of the incoming light over the range of 420 to 700 nm. The field is compressed by 0.67x (when using a Color Filter Wheel) allowing full corner-to-corner illumination of the ST10E chip with most catadioptric telescopes. This design does not add coma to the wavefront, and thus can be used with all flat-field and coma-free telescopes such as Maks, Ritchey-Cretiens and refractors. The inherent resolution of the telescope is not compromised when using this compressor