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 chant also contain repeated texts, which their musical structures often exploit. Technically, the Ite missa est and the Benedicamus Domino, which conclude the Mass, belong to the Ordinary. They have their own Gregorian melodies, but because they are short and simple, and have rarely been the subject of later musical composition, they are often omitted in discussion. Gregorian chant is sung in the canonical hours of the monastic Office, primarily in antiphons used to sing the Psalms, in the Great Responsories of Matins, and the Short Responsories of the Lesser Hours and Compline. The psalm antiphons of the Office tend to