Check the listing for details. F/6.3 Reducer Corrector Deceleration Lens 94175 for C Series Telescope. Condition: New. Listed at 79.89 USD. 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 smart accessory makes it possible to use a dual focal ratio instrument, without compromising image quality The Reducer/Corrector is f/6.3 for C5, C6, C8, c9 ¼ and C11 telescopes and f/7 for the C14 telescope Product description: This combination of focal reducer and field corrector lens accessory works with all Celestron 5 ", 6", 8 ", 9 1/4", 11 "and 14" Schmidt-Cassegrain telescopes. This smart accessory makes it possible to use a dual focal ratio instrument, without compromising image quality. The Reducer/Corrector is f/6.3 for C5, C6, C8, c9 ¼ and C11 telescopes and f/7 for the C14 telescope. If offers wide fields of view with each Schmidt-Cassegrain telescope. Used for astrophotography, it reduces exposure time by a factor of 3. Celestron does not provide an f/6.3 Schmidt-Cassegrain telescope, because the design is impractical, with a large central obstruction, and results loss in contrast. These, added to the inability use longer focal ratio for certain objects, led Celestron to the four-element, fully multicoated f/6.3 Reducer/Corrector. Results are amazing both visual and photographic. THE #94175 REDUCER/CORRECTOR LENS IS NOT COMPATIBLE WITH CELESTRON EDGEHD OPTICAL SYSTEMS. This lens reduction lens/field correction lens mounting can be used in the Startent 5-inch, 8-inch, 9.25-inch, 11-inch and 14-inch Schmidt - Cassegrain telescope. This flexible accessory allows the telescope to two coke proportions without compromising quality. This reduction lens/correction lens can be C5, C6, C8, c9.25 coke ratio f / 6.3, and C14 coke ratio can become f / 7. Use this reduction lens can increase the field of view, in astronomical photography can reduce the exposure time. Star Treon do not offer f / 6.3 Schmidt Cassegrain telescope, because such a design is not possible, there will be a large central block and lead to a drop contrast. This section f / 6.3 of the lens/corrective mirror is a four piece design, full surface coating. Use this lens in visual and photography have a very good performance.