Klevtsov–Cassegrain telescope

The Klevtsov–Cassegrain telescope is a type of catadioptric Cassegrain telescope that uses a spherical primary mirror and a sub-aperture secondary corrector group composed of a small lens and a Mangin mirror.

[1][2] The secondary Mangin mirror (M 2 ) and the meniscus corrector (C) are held in place by a spider vane and the front of the telescope tube is otherwise open.

These types of telescopes have the disadvantage of the spider, which holds the corrector, causing diffraction artifacts[3] and, since multiple surfaces are involved, achieving good aberration correction can be very complex.

[4] This design was originally envisaged by G. I. Popov with a practical implementation by Yuri A. Klevtsov.

Commercial manufacturers of the design include Novosibirsk TAL and Vixen.