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
Gregorian Antiphonary respect it as a work thenceforward irreformable, as a traditional deposit which he refused to disturb and re-order. It is not easy to say, or even to convey an idea of, what this primitive edition of the antiphonary may have contained; but there can be no doubt that it contained in their actual order the Lenten communion-antiphons, and is certainly anterior to Gregory III and to Gregory II. This fact alone proves the existence of an antiphonal collection, known as the Gregorian antiphonary, prior to the time of Pope Gregory II. Gregorian Antiphonary The Gregorian Antiphonary was an early Christian