f/6.3 Reducer Corrector for C Series Telescopes This combination focal reducer and field corrector lens accessory works with all Celestron 5inch, 6inch, 8inch, 9 1/4inch, 11inch and 14inch 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. Cassegrain telescope, because the design is impractical, with a large central obstruction, and resulting loss in contrast. This, added to the inability to utilize longer focal ratios for certain objects, led Celestron to design the four-element, fully multicoated f/6.3 Reducer/Corrector. Results are amazing both visually and photographically. Color: As shown Material: Metal+Glass Package Contents: 1 * Astronomical telescope F6.3 focal reducer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.