This Celestron EdgeHD 0.7x focal reducer turns your 8" f/10 EdgeHD telescope into a full f-stop faster f/7 scope, increasing your photographic field of view by 43% and cutting your deep space exposure times in half .
This Celestron EdgeHD 0.7x focal reducer is a 4-element lens system that converts your 8" f/10 EdgeHD scope or optical tube into a fast f/7 (1422mm focal length) optical system.
The Celestron reducer increases your photographic field of view by 43% to better capture wide field images and cuts your deep space exposure times in half, all the while maintaining the flat-field performance of the EdgeHD's native optical design. It provides an intermediate focal ratio between the 8" EdgeHD's native f/10 and the f/2 ratio that is available with an optional Hyperstar accessory, making the EdgeHD the most complete imaging system in its price range.
The 8" EdgeHD reducer is optimized for use with APS-C size CCD sensors, which are found in most DSLR cameras and in the Celestron Nightscape CCD cameras.
The EdgeHD focal reducer uses high index optical elements, including exotic extra low dispersion rare-earth Lanthanum elements, to provide high contrast imaging while minimizing chromatic aberration. All air to glass lens surfaces are fully multicoated for maximum light transmission and color correction. Lens edges are blackened to minimize internal reflection and maximize image contrast.
The 8" EdgeHD reducer threads directly onto the rear cell of all 8" EdgeHD optical tubes, in place of the scope's visual back. The reducer shortens the 8HD's photographic back focus from 133mm to 105mm (measured from the reducer to the image plane). Used with an optional #93644 8" EdgeHD T-adapter (with its extension tube removed) it is optimally matched to DSLRs, Celestron Nightscape CCDs, or any other camera with the standard 55mm back focus, with no other focal extension rings or accessories needed. The 105mm back focus allows its use with some off-axis guiders, such as the Celestron #OAG93648, but some additional accessories and/or spacers may be required.
Threading the CNC machined aluminum housing of the reducer directly onto the rear cell reduces mechanical vignetting and maximizes imaging train rigidity. The CNC machined aluminum housing assures precise spacing and alignment of the optical elements. Threaded metal covers on both sides of the lens assembly protect your investment from dust and scratches.
