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16-397: Compilation for the first version, Astronomische Gesellschaft Katalog 1 AGK1 , was started in 1867, directed by Friedrich Argelander and published between 1890 (three sections from the observatories at Oslo, Helsinki, and Neuchâtel Observatory ) and 1924 (final section: Algiers Observatory ), listing 200 000 stars down to ninth magnitude . The second version, AGK2 , was started in

32-488: 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. The Bonner Durchmusterung (abbreviated BD), was initiated by Friedrich Argelander and using observations largely carried out by his assistants, which resulted in

48-509: 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

64-655: A manner similar to the BD numbering system. A few decades later, the positional accuracy of the Durchmusterung catalogues began to be insufficient for many projects. To establish a more exact reference system for the Bonner Durchmusterung, astronomers and geodesists began to work on a fundamental celestial coordinate system based on the Earth's rotation axis , the vernal equinox and the ecliptic plane in

80-836: Is a stub . You can help Misplaced Pages by expanding it . Friedrich Argelander Friedrich Wilhelm August Argelander (22 March 1799 – 17 February 1875) was a German astronomer . He is known for his determinations of stellar brightnesses, positions, and distances. Argelander was born in Memel in the Kingdom of Prussia (now Klaipėda in Lithuania ), the son of a father of Finnish descent, Johann Gottlieb Argelander, and German ( Prussian ) mother, Dorothea Wilhelmina Grünhagen. He studied with Friedrich Bessel , whose assistant he became in 1820, and obtained his Ph.D. in 1822 at University of Königsberg . From 1823 until 1837, Argelander

96-408: Is exemplified by "BD−16 1591", which is the BD number of Sirius . This number signifies that in the catalog, Sirius is the 1591st star listed in the declination zone between −16 and −17 degrees, counting from 0 hours right ascension . Stellar positions and zone boundaries use an equinox for the epoch of B1855.0 . Many astronomical research projects—from studies of celestial mechanics and

112-480: The Solar System , up to the nascent field of astrophysics —were made possible by the publication of the atlas and data of the Bonner Durchmusterung. However, a deficiency of the BD was that it did not cover the whole sky, because far southern stars are not visible from Germany. This led the scientific community to supplement the BD with two additional astrometric surveys carried out by observatories located in

128-621: The 1920s, and published between 1951 and 1958 using photographic data obtained from the Bonn and Hamburg Observatories . Karl Friedrich Küstner was involved in the planning for star catalog AGK2 with the Bonn part then directed by Ernst Arnold Kohlschütter . The third version, AGK3 , was started in 1956 and published in 1975. It contains 183,145 stars north of declination –2° with mean positional errors of ±0.13 " and mean proper motion errors of ±0.009"/year. This astronomical catalog article

144-475: The 20th century. In 1886 Eduard Schönfeld , also in Bonn, 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. The format of a BD number

160-620: The Prussian royal family fled to Memel after the Battle of Jena–Auerstedt during the Napoleonic Wars . Argelander excelled in developing effective, simple and fast methods for measuring star positions and magnitudes, thereby making a pioneering work for modern astronomy. He also measured star distances with heliometers . His, and his collaborators', great practical works of star cataloging and variable star research were made possible by

176-620: The Southern Hemisphere: Córdoba, Argentina , and Cape Town , South Africa. The Cordoba Durchmusterung (abbreviated CD, or, less commonly, CoD) was made visually (as was the BD), but the Cape Photographic Durchmusterung (CP or CPD) was conducted by the then-new photographic technique, which had just been shown to have sufficient accuracy. The southern stars are identified by CD and CPD numbers in

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192-665: The late 19th century. This astrometric project led to the Catalogues of Fundamental Stars of the Berlin observatory, and was used as an exact coordinate frame for the BD and AGK. It was modernized in the 1920s ( FK3 , mean accuracy ±1″), and in 2000 ( FK6 , accuracy 0.1″) as successive steps of cosmic geodesy . Together with radioastronomical measurements, the FK6 accuracy was better than ±0.1″. The Hipparcos satellite operated between 1989 and 1993 and observed around 118,000 stars over

208-750: The sky. This was the last star map to be published without the use of photography. In 1863, Argelander helped lead in the founding of an international organization of astronomers named the Astronomische Gesellschaft . 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 Durchmusterung ('run-through examination'),

224-509: The systematic usage of then newly developed techniques. Argelander was the first astronomer to begin a careful study of variable stars . Only a handful were known when he began, and he was responsible for introducing the modern system of identifying them. He also made a rough determination of the direction in which the Sun was moving. In 1842, he discovered that Groombridge 1830 had a very high proper motion . For many decades its proper motion

240-710: Was the head of the Finnish observatory , first in Turku and then in Helsinki . He then moved to Bonn , Germany . There he designed and built a new observatory at the University of Bonn with funding approved directly by King Frederick William IV whom Argelander had become friends with in his childhood. This lifelong friendship had started when the then crown prince temporarily lived in Argelander's parents house after

256-486: Was the highest known; today it still occupies third place. For a time, it was known as Argelander's Star . Together with Adalbert Krüger and Eduard Schönfeld , Argelander was responsible for the star catalogue known as the Bonner Durchmusterung , published between 1859 and 1862, which gave the positions and brightness of more than 324,000 stars, although it did not cover much of the southern half of

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