37% Focal Length Reduction: Astronomia F/6.3 Focal Reducer shortens the effective focal length of Schmidt-Cassegrain telescope optical system by 37 percent; transform your f/10 system into a faster f/6.3 configuration for significantly wider field of view Universal SCT Compatibility: Designed with SCT thread for all Celestron Schmidt-Cassegrain telescopes ( 5 inch 6 inch 8 inch 9.25 inch 11 inch & 14 inch ) including NexStar SE/Evolution/EdgeHD series, making it the ultimate focal reducer for SCT owners Advanced Multi-Coated Optical System for Optimal Clarity: Features 4-element fully multi-coated optics with 41mm clear aperture, ensuring maximum reflection and minimized chromatic aberration for crisp celestial views Excellent & Essential Telescope Accessory: The essential f/6.3 reducer-corrector for deep-sky imaging as a clever accessory makes it possible to have a dual focal ratio instrument without sacrificing image quality during astronomical observation Premium Aluminum & Protective Design: CNC-machined aluminum alloy with shock-absorbing rubber housing; complete with dust caps (front/rear) & storage case for protecting focal reducer from impacts, moisture during transport and storage This combination focal reducer and field corrector lens accessory works with all Celestron 5", 6", 8", 9 1/4", 11" and 14" Schmidt-Cassegrain telescopes. This clever accessory makes it possible to have a dual focal ratio instrument, without sacrificing image quality. The Reducer/Corrector is f/6.3 for C5, C6, C8, C9¼ and C11 telescopes and f/7 for the C14 telescope.If offers wide fields of view with any Schmidt-Cassegrain telescope. Used for astrophotography, it reduces exposure time by a factor of 3.