Imagine having two telescopes in one - a long focal length instrument for lunar and planetary work and a short focal length scope for deep sky observing and astrophotography. With the Celestron Reducer/Corrector Lens, that’s precisely what you get. Explicitly designed for Celestron Schmidt-Cassegrain telescopes, this unique lens reduces your telescope’s focal length and f/ ratio by 37%, turning your long focal length telescope into a fast, short focal length instrument. A f/10 focal ratio now achieves a f/6.3, while an f/11 focal ratio now achieves a f/7. For visual use, this means you get lower power with the same eyepiece and a wider field of view. Photographically you also get a wider field and much shorter exposures. The Reducer/Corrector is easy to install by threading the unit onto the rear cell of your Schmidt-Cassegrain telescope (or the reducer plate of the C11 and C14). Once installed, you can add additional accessories like T-Adapters, 1.25” Visual Back, Star Diagonal, or Off-Axis Guider. The Reducer/Corrector can also be used for terrestrial digiscoping. The faster f/ratio allows you to use slower film or shoot in lower light level situations and still properly expose your subject. This fully multi-coated lens provides maximum light transmission with near full-field illumination. The lens is housed in machined aluminum for are machined aluminum black anodized. The internal surfaces are blackened and glare-threaded to provide the highest contrast. The lens has a knurled surface, providing a tremendous gripping surface for threading/unthreading.