Schmidt camera optical axis of the Schmidt design creates a Schmidt-Newtonian telescope. The addition of a convex secondary mirror to the Schmidt design directing light through a hole in the primary mirror creates a Schmidt-Cassegrain telescope. The last two designs are popular with telescope manufacturers because they are compact and use simple spherical optics. A short list of notable and/or large aperture Schmidt cameras. Schmidt camera A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt in 1930. Some notable
Hilbert–Schmidt integral operator Hilbert–Schmidt integral operator In mathematics, a Hilbert–Schmidt integral operator is a type of integral transform. Specifically, given a domain (an open and connected set) Ω in "n"-dimensional Euclidean space R, a Hilbert–Schmidt kernel is a function "k" : Ω × Ω → C with (that is, the "L"(Ω×Ω; C) norm of "k" is finite), and the associated Hilbert–Schmidt integral operator is the operator "K" : "L"(Ω; C) → "L"(Ω; C) given by Then "K" is a Hilbert–Schmidt operator with Hilbert–Schmidt norm Hilbert–Schmidt integral operators are both continuous (and hence bounded) and compact (as with all Hilbert–Schmidt operators). The concept of