Schmidt camera 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 examples are the Samuel Oschin telescope (formerly Palomar Schmidt), the UK Schmidt Telescope and the ESO Schmidt; these provided the major source of all-sky photographic imaging from 1950 until 2000, when electronic detectors took over. A recent example is the Kepler spacecraft exoplanet finder. Other related designs are the Wright Camera and Lurie–Houghton telescope. The Schmidt camera was invented by German-Estonian optician
Gregorian chant Multi-voice elaborations of Gregorian chant, known as organum, were an early stage in the development of Western polyphony. Gregorian chant was traditionally sung by choirs of men and boys in churches, or by men and women of religious orders in their chapels. It is the music of the Roman Rite, performed in the Mass and the monastic Office. Although Gregorian chant supplanted or marginalized the other indigenous plainchant traditions of the Christian West to become the official music of the Christian liturgy, Ambrosian chant still continues in use in Milan, and there are musicologists exploring both that and the Mozarabic