MPCC Mark III Comma Corrector

The only coma corrector for Newtonian telescopes that does not increase the telescope's focal length or reduce the field of view

Large aspherical mirrors are excellent for deep-sky photography, providing the largest possible field of view combined with high luminosity. However, these parabolic mirrors exhibit coma (and, to a lesser extent, astigmatism). Coma is the distortion of star images at the edge of the field of view, which significantly reduces the effective useful field of view. Several manufacturers offer coma correctors to compensate for these distortions. These are lens elements placed close to the telescope's focal point and thus reduce coma effects. However, the drawback of this solution is that it lengthens the telescope's focal length.

The MARK III Multipurpose Coma Corrector (MPCC III) eliminates virtually all coma without changing focal length. The unique lens arrangement is Phantom Group, with multi-coating on all glass-air interfaces. This provides maximum transmission over a very wide spectral range, from UV to NIR. Stars are seen as points across the entire field of view. Furthermore, the MPCC can be used for both visual and photographic applications.

The MPCC III is the most widely used coma corrector for both visual and photographic use. It fits almost all 2" focusers and off-axis guides. For greater insertion depth in the focuser and more backfocus, the 2" stop ring can be unscrewed.