| Alternative names | Bonner Durchmusterung |
|---|---|
| Survey type | star catalogue  |
Inastronomy,Durchmusterung orBonner Durchmusterung (BD) is anastrometricstar catalogue of the whole sky, published by theBonn Observatory in Germany from 1859 to 1863, with an extension published in Bonn in 1886. The name comes fromDurchmusterung ('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 inelectromagnetic wavelengths shorter or longer thanvisible light waves.
The Bonner Durchmusterung (abbreviated BD), was initiated byFriedrich Argelander and using observations largely carried out by his assistants, which resulted in a catalogue of the positions andapparent 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,[1] and was the basis for theAstronomische Gesellschaft Katalog (AGK) andSmithsonian Astrophysical Observatory Star Catalog (SAO) catalogues of the 20th century. In 1886Eduard 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 inCordobaArgentina 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 is exemplified by "BD−16 1591", which is the BD number ofSirius. This number signifies that in the catalog, Sirius is the 1591st star listed in thedeclination zone between −16 and −17 degrees, counting from 0 hoursright ascension.[2] Stellar positions and zone boundaries use anequinox for theepoch of B1855.0.
Many astronomical research projects—from studies ofcelestial mechanics and theSolar System, up to the nascent field ofastrophysics—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 byobservatories located in the Southern Hemisphere:Córdoba, Argentina, andCape 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 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 andgeodesists began to work on a fundamentalcelestial coordinate system based on theEarth's rotation axis, the vernalequinox and theecliptic plane in the late 19th century. This astrometric project led to theCatalogues 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 ofcosmic geodesy. Together withradio-astronomical measurements, the FK6 accuracy was better than ±0.1″.
TheHipparcos satellite operated between 1989 and 1993 and observed around 118,000 stars over the whole sky. Three star catalogues were published from its data:
TheGaiaspace observatory, launched in December 2013, has catalogued a billion stars with an accuracy down to 20microarcseconds (0.00002″).
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