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 Gregorian chant Gregorian chant is the central tradition of Western plainchant, a form of monophonic, unaccompanied sacred song of the Roman Catholic Church. Gregorian chant developed mainly in western and central Europe during the 9th and 10th centuries, with later additions and redactions. Although popular legend credits Pope Gregory I with inventing Gregorian chant, scholars believe that it arose from a later Carolingian synthesis of Roman chant and Gallican chant. Gregorian chants were organized initially into four, then eight, and finally 12 modes. Typical melodic features include a characteristic ambitus, and also characteristic intervallic patterns relative to a referential mode