Ameniscus corrector is anegative meniscus lens that is used to correctspherical aberration inimage-forming optical systems such ascatadioptric telescopes. It works by having the equal but oppositespherical aberration of theobjective it is designed to correct (usually aspherical mirror).
Meniscus correctors are used as full aperture correctors, most commonly in aMaksutov telescope sub type called the Gregory or “spot”Maksutov–Cassegrain telescope. They are also used in theBouwers meniscus telescope. There are Maksutov variations that use the same principle but place the meniscus lens as a sub-aperture corrector near the focus of the objective. There are other sub-aperture meniscus corrector catadioptric telescopes such as theArgunov–Cassegrain telescope and theKlevtsov–Cassegrain telescope.
The idea of using the spherical aberration of a meniscus lens to correct the opposite aberration in a sphericalobjective dates back as far as W. F. Hamilton’s 1814Hamiltonian telescope, in Colonel A. Mangin's 1876Mangin mirror, and also appears inLudwig Schupmann’sSchupmann medial telescope near the end of the 19th century.
After the invention of the wide-fieldSchmidt camera in the early 1930s, at least four optical designers in early 1940s war-torn Europe came up with the idea of replacing the complicatedSchmidt corrector plate with a simpler meniscus lens, includingAlbert Bouwers,Dmitri Dmitrievich Maksutov, K. Penning, andDennis Gabor.[1] All of these designs used full aperture correctors (ameniscus corrector shell) to create a wide-field telescope with little or nocoma orastigmatism. Albert Bouwers built a prototypemeniscus telescope in August 1940 and patented it in February 1941. His design had the mirror and meniscus lens with surfaces that had a common centre of curvature, called a "concentric" or "monocentric" telescope. The design had an ultrawide field of view but did not correctchromatic aberration and was only suitable as a monochromatic astronomical camera. Dmitri Maksutov built a prototype for a similar type of meniscus telescope, theMaksutov telescope, in October 1941, and patented it in November of that same year.[2] His design corrected most spherical aberration and also corrected for chromatic aberration by placing a weakly negative-shaped meniscus corrector closer to the primary mirror.Dennis Gabor’s 1941 design was a non-monocentric meniscus corrector.[3] Wartime secrecy kept these designers from knowing about each other's design, making each invention independent.