Celestron Reduction lens f/6.3

Reducer / Corrector f/6.3 - with 2" female thread (not for Edge-HD) This useful lens corrector system kills several birds with one stone: The 4-lens focal reducer shortens the focal length of all Schmidt-Cassegrain telescopes by a factor of 0.63. The focal ratio changes by the same amount from 1:10 to 1:6.3, resulting in a significantly larger field of view and exposure times that are shorter by a factor of 3. The optical correction system flattens the slightly curved field of view of all Schmidt-Cassegrain telescopes, providing a fully corrected, vignetting-free "richfield" field of view with a diameter of 24 mm. The focal lengths of the Celestron SC telescopes change as follows: C-5: from 1250 to 788 mm / f 6.3 C-8: from 2000 to 1260 mm / f 6.3 C-9: from 2350 to 1480 mm / f 6.3 C-11: from 2800 to 1764 mm / f 6.3 C-14: from 3910 to 2457 mm / f 7.3 The Celestron Focal Reducer can also be used visually. It has the Celestron SC thread on both sides and is screwed directly to the tube of the telescopes. It can also be used in combination with the Radial Guider for photography and CCD cameras.