Baader MPCC Coma Corrector (2")

Large, fast parabolic mirrors are desirable for deep sky photography and observation because they offer low power wide field views. However, the main problem with fast parabolic mirrors is that they introduce coma (and to a lesser degree, astigmatism).

Coma is distortion of star images near the edge of the field that reduces the size of the usable field of view. To eliminate coma, several companies have introduced coma correctors, lenses that are placed near the focus point and reduce the severity of the coma. The problem is that most of these increase the telescope’s f/ratio and focal length.

The Multipurpose Coma Corrector (MPCC) virtually eliminates coma without increasing the focal ratio of your telescope. This unique lens design utilizes a multi-coating on all air-to-glass surfaces to allow 98% transmission (transmission peaks in the hydrogen-alpha region of the spectrum).

Although the MPCC is optimized for f/4.5 mirrors, it works well with mirrors from f/4 to f/6. Stars remain 12 micron dots over the entire field.
In addition, the MPCC can be used both visually and photographically.