Maksutov telescope

Maksutov telescope. A schematic diagram of the optical arrangement. A reflecting telescope incorporating a deeply curved meniscus lens, which corrects the optical aberrations of the spherical primary mirror to give high-quality images over a wide field of view. It was invented by D. D. Maksutov (1896-1964). The practical arrangement is typically a Cassegrain system. A small secondary mirror is fixed to the back of the correcting lens and the image is formed just behind the primary mirror, which has a small central hole (see illustration). The difficulty of making large correcting lenses limits the professional application of the design, but the compactness of the tube, the wide field of view and low focal ratio have made Maksutov telescopes popular with amateurs.