The Celestron T-Adapter SC is for all Celestron Schmidt-Cassegrain telescopes. Simply screws onto the rear cell. It then means that you can attach your DSLR camera to the prime focus of your telescope. With this arrangement it can be used for terrestrial & short exposure lunar & planetary photography. With the addition of a guide-scope, it can also be used for long exposure deep-sky photography. Requires the use of a T-Ring to suit your camera type.