Durchmusterung

In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, published by the Bonn Observatory in Germany from 1859 to 1863, with an extension published in Bonn in 1886. The name comes from ('run-through examination'), a German word used for a systematic survey of objects or data. The term has sometimes been used for other astronomical surveys, including not only stars, but also the search for other celestial objects. Special tasks include celestial scanning in electromagnetic wavelengths shorter or longer than visible light waves.

==Original catalog== The Bonner Durchmusterung (abbreviated BD), was initiated by Friedrich Argelander and using observations largely carried out by his assistants, which resulted in a catalogue of the positions and apparent magnitudes of 342,198 stars down to approximate apparent magnitude 9.5 and covering the sky from 90°N to 2°S declination. The catalogue, published in three parts, was accompanied by charts plotting the positions of the stars, and was the basis for the Astronomische Gesellschaft Katalog (AGK) and Smithsonian Astrophysical Observatory Star Catalog (SAO) catalogues of the 20th century. In 1886 Eduard Schönfeld, also in Bonn as Argelander's successor and previously as an assistant to Argelander on the original BD project, published an extension from 2°S to 23°S declination. (A further extension from an observatory in Cordoba Argentina was published in five parts between 1892 and 1932 to cover the southern sky from 22°S to 90°S declination.) BD star numbers are still used and allow the correlation of the work with modern projects.