Astrophysical Institute Potsdam
Encyclopedia
Leibniz Institute for Astrophysics Potsdam (AIP) is a German research institute. It is the successor of the Berlin Observatory
Berlin Observatory
The Berlin Observatory is a series of observatories and related organizations in and around the city of Berlin in Germany, starting from the 18th century...

 founded in 1700 and of the Astrophysical Observatory Potsdam (AOP) founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

. The AIP was founded in 1992, in a re-structuring following the German Reunification
German reunification
German reunification was the process in 1990 in which the German Democratic Republic joined the Federal Republic of Germany , and when Berlin reunited into a single city, as provided by its then Grundgesetz constitution Article 23. The start of this process is commonly referred by Germans as die...

.

The AIP is privately funded and member of the Leibniz Association. It is located in Babelsberg
Potsdam-Babelsberg
Babelsberg is the largest district of the Brandenburg capital Potsdam in Germany. The affluent neighbourhood named after a small hill on the Havel river is famous for Babelsberg Palace and Park, part of the Palaces and Parks of Potsdam and Berlin UNESCO World Heritage Site, as well as for Studio...

 in the state of Brandenburg
Brandenburg
Brandenburg is one of the sixteen federal-states of Germany. It lies in the east of the country and is one of the new federal states that were re-created in 1990 upon the reunification of the former West Germany and East Germany. The capital is Potsdam...

, just west of Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, though the Einstein Tower
Einstein Tower
The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

 solar observatory and the great refractor telescope
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...

 on Telegrafenberg in Potsdam
Potsdam
Potsdam is the capital city of the German federal state of Brandenburg and part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin city centre....

 belong to the AIP.

The key topics of the AIP are cosmic magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

s (magnetohydrodynamics
Magnetohydrodynamics
Magnetohydrodynamics is an academic discipline which studies the dynamics of electrically conducting fluids. Examples of such fluids include plasmas, liquid metals, and salt water or electrolytes...

) on various scales and extragalactic astrophysics. Astronomical and astrophysical fields studied at the AIP range from solar
Solar physics
For the physics journal, see Solar Physics Solar physics is the study of our Sun. It is a branch of astrophysics that specializes in exploiting and explaining the detailed measurements that are possible only for our closest star...

 and stellar physics
Stellar physics
Stellar physics, is a term coined for the research concerning the formation, evolution, interior and the atmospheres of stars. The understanding of the birth and death of stars requires the application of almost all branches of modern physics...

 to stellar
Stellar evolution
Stellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...

 and galactic evolution
Galaxy formation and evolution
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby...

 to cosmology
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

.

The institute also develops research technology in the fields of spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...

 and robotic telescope
Robotic telescope
A robotic telescope is an astronomical telescope and detector system that makes observations without the intervention of a human. In astronomical disciplines, a telescope qualifies as robotic if it makes those observations without being operated by a human, even if a human has to initiate the...

s. It is a partner of the Large Binocular Telescope
Large Binocular Telescope
Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

 in Arizona, has erected robotic telescopes in Tenerife
Tenerife
Tenerife is the largest and most populous island of the seven Canary Islands, it is also the most populated island of Spain, with a land area of 2,034.38 km² and 906,854 inhabitants, 43% of the total population of the Canary Islands. About five million tourists visit Tenerife each year, the...

 and the Antarctic, develops astronomical instrumentation for large telescopes such as the VLT
VLT
VLT may stand for:* Very Large Telescope, a system of four large optical telescopes organized in an array formation, located in northern Chile...

 of the ESO
European Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...

. Furthermore, work on several e-Science
E-Science
E-Science is computationally intensive science that is carried out in highly distributed network environments, or science that uses immense data sets that require grid computing; the term sometimes includes technologies that enable distributed collaboration, such as the Access Grid...

 projects are carried out at the AIP.

Timetable

1700 Introduction of the so-called "Improved Calendar" in the Protestant states of Germany
1700 May 10 Enactment of the calendar patent for the Berlin Observatory
1700 May 18 Appointment of Gottfried Kirch as director of the observatory
1700 Jul 11 Foundation of the Brandenburg Society
1711 Construction of the first observatory in Berlin
1832–35 Construction of the new observatory by Karl Friedrich Schinkel
1846 Discovery of the planet Neptune by Johann Gottfried Galle
1865 Appointment of Wilhelm Julius Foerster as director
1874 Foundation of the Astronomical Recheninstitut
1874 Foundation of the Astrophysical Observatory Potsdam (AOP)
1876–79 Construction of the main building of the AOP on the Telegrafenberg at Potsdam
1881 First Michelson experiment in Potsdam
1886 Discovery of canal rays by Eugen Goldstein
1888 Discovery of the polar motion of the Earth by Karl Friedrich Küstner
1888 First photographic determination of a radial velocity by Hermann Carl Vogel
1896 Experiments to find solar radio emissions by Johannes Wilsing and Julius Scheiner
1899 Completion of the Great Refractor at Potsdam
1904 Appointment of Karl Hermann Struve as director of the Berlin Observatory
1909 Appointment of Karl Schwarzschild as director of the AOP
1911–13 Construction of the observatory in Babelsberg
1913 Relocation of the Berlin Observatory to Babelsberg
1913 Introduction of photoelectric photometry by Paul Guthnick in Babelsberg
1915 Completion of the Large Refractor in Babelsberg
1921–24 Construction of the Einstein Tower on the Telegrafenberg
1924 Completion of the 1.22 m telescope in Babelsberg
1931 Association of the Sonneberg Observatory to the Babelsberg Observatory
1947 Jan 1 Takeover of AOP and Babelsberg Observatory by the German Academy of Sciences
1954 Start of radio observations in Tremsdorf
1960 Completion of the 2 m telescope in Tautenburg
1969 Foundation of the Central Institute of Astrophysics
1992 Jan 1 Establishment of the AIP; appointment of Karl-Heinz Rädler as scientific chairman
1998 Appointment of Günther Hasinger as scientific chairman of the AIP
2001 Appointment of Klaus G. Strassmeier as scientific chairman of the AIP
2004 Appointment of Matthias Steinmetz as scientific chairman of the AIP
2005 LBT "First Light"
2006 Re-inauguration of the Great Refractor
2006 Inauguration of STELLA on Tenerife
2011 Name of institute changed from "Astrophysical Institute Potsdam" to "Leibniz Institute for Astrophysics Potsdam"

Origin

The history of astronomy in Potsdam
Potsdam
Potsdam is the capital city of the German federal state of Brandenburg and part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin city centre....

 really began in Berlin in 1700. Initiated by Gottfried W. Leibniz
Gottfried Leibniz
Gottfried Wilhelm Leibniz was a German philosopher and mathematician. He wrote in different languages, primarily in Latin , French and German ....

, on July 11, 1700 the "Brandenburgische Societät" (later called the Prussian Academy of Sciences
Prussian Academy of Sciences
The Prussian Academy of Sciences was an academy established in Berlin on 11 July 1700, four years after the Akademie der Künste or "Arts Academy", to which "Berlin Academy" may also refer.-Origins:...

) was founded by the elector Friedrich III
Frederick I of Prussia
Frederick I , of the Hohenzollern dynasty, was Elector of Brandenburg and Duke of Prussia in personal union . The latter function he upgraded to royalty, becoming the first King in Prussia . From 1707 he was in personal union the sovereign prince of the Principality of Neuchâtel...

 in Berlin. Two months earlier the national calendar monopoly provided the funding for an observatory. By May 18 the first director, Gottfried Kirch
Gottfried Kirch
Gottfried Kirch was a German astronomer. The son of a shoemaker in Guben, Electorate of Saxony, Kirch first worked as a calendar-maker in Saxonia and Franconia. He began to learn astronomy in Jena, and studied under Hevelius in Danzig...

, had been appointed. This happened in a hurry, because the profits from the national basic calendar, calculated and sold by the observatory, should have been the financial source for the academy. This kind of financing existed until the beginning of the 19th century, but the basic calendar was calculated until very recently (it passed away after the "Wende" in 1991).

In 1711 the first observatory was built in Dorotheen Street in Berlin and in 1835 a new observatory building, which was designed by the famous architect Karl Friedrich Schinkel
Karl Friedrich Schinkel
Karl Friedrich Schinkel was a Prussian architect, city planner, and painter who also designed furniture and stage sets. Schinkel was one of the most prominent architects of Germany and designed both neoclassical and neogothic buildings.-Biography:Schinkel was born in Neuruppin, Margraviate of...

, was completed in Linden Street (near Hallesches Tor). Alexander von Humboldt
Alexander von Humboldt
Friedrich Wilhelm Heinrich Alexander Freiherr von Humboldt was a German naturalist and explorer, and the younger brother of the Prussian minister, philosopher and linguist Wilhelm von Humboldt...

 was then promoting astronomy by his famous "Kosmos" lectures in 1827–28. He played an important role in providing the funds for both observatory and instruments.

The Berlin Observatory
Berlin Observatory
The Berlin Observatory is a series of observatories and related organizations in and around the city of Berlin in Germany, starting from the 18th century...

 became known worldwide when Johann Gottfried Galle
Johann Gottfried Galle
Johann Gottfried Galle was a German astronomer at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view the planet Neptune, and know what he was looking at...

 discovered the planet Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...

 in 1846. The discoveries of the canal rays
Anode ray
Anode rays are beams of positive ions that are created by certain types of gas discharge tubes. They were first observed in Crookes tubes during experiments by the German scientist Eugen Goldstein, in 1886. Later work on anode rays by Wilhelm Wien and J. J...

 by Eugen Goldstein
Eugen Goldstein
Eugen Goldstein was a German physicist. He was an early investigator of discharge tubes, the discoverer of anode rays, and is sometimes credited with the discovery of the proton.- Life :...

 in 1886 in the physical laboratory of the observatory and of the variation in the altitude of the Earth's pole by Karl Friedrich Küstner
Karl Friedrich Küstner
Karl Friedrich Küstner was a German astronomer who also made contributions to Geodesy. In 1888 he reportedly discovered the Polar motion of the Earth. In 1910 he received the Gold Medal of the Royal Astronomical Society for cataloguing stars and detecting latitude variation.- References :...

 in 1888 were likewise important.

The last two scientific events took place when Wilhelm Julius Foerster
Wilhelm Julius Foerster
Wilhelm Julius Foerster was a German astronomer, father of the pacifist and ethicist Friedrich Wilhelm Foerster. His name can also be written Förster, but is usually written "Foerster" even in most German sources where 'ö' is otherwise used in the text.A native of Grünberg, Silesia, he worked as...

 was director of the observatory, which was meanwhile attached to the University of Berlin. He prepared the basis for the astronomical observatories in Potsdam: in 1874 the foundation of the AOP on the Telegrafenberg and in 1913 the removal of the Berlin Observatory to Babelsberg.

Foundation of the Astrophysical Observatory Potsdam (AOP)

In the middle of the 19th century spectral analysis
Spectral analysis
Spectral analysis or Spectrum analysis may refer to:* Spectrum analysis in chemistry and physics, a method of analyzing the chemical properties of matter from bands in their visible spectrum...

 was developed by Gustav Kirchhoff
Gustav Kirchhoff
Gustav Robert Kirchhoff was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects...

 and Robert Bunsen
Robert Bunsen
Robert Wilhelm Eberhard Bunsen was a German chemist. He investigated emission spectra of heated elements, and discovered caesium and rubidium with Gustav Kirchhoff. Bunsen developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organoarsenic...

. It enabled the acquisition of information on the physical parameters and chemical abundances of stars, by the spectral analysis of their light. Foerster recognized these possibilities and initiated the building of a solar observatory in 1871 as a memorial to the crown prince, in which he emphasized the importance and profit of solar research. This idea was soon extended to the whole of astrophysics.

The site of the observatory was chosen on a hill south of Potsdam
Potsdam
Potsdam is the capital city of the German federal state of Brandenburg and part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin city centre....

, the Telegrafenberg, on which had been, from 1832 to 1848, a relay station of the military telegraph from Berlin to Koblenz. On 1 July 1874 the AOP was founded. Even before the construction of the observatory had started in the autumn of 1876, solar observations were being made from the tower of the former military orphanage in Linden Street in Potsdam by Gustav Spörer
Gustav Spörer
Friederich Wilhelm Gustav Spörer was a German astronomer.He is noted for his studies of sunspots and sunspot cycles. In this regard he is often mentioned together with Edward Maunder. Spörer was the first to note a prolonged period of low sunspot activity from 1645 to 1715...

. The construction work started in 1876; the main observatory building and its equipment were finished in the autumn of 1879.

The AOP was managed by a board of directors comprising Wilhelm Julius Foerster
Wilhelm Julius Foerster
Wilhelm Julius Foerster was a German astronomer, father of the pacifist and ethicist Friedrich Wilhelm Foerster. His name can also be written Förster, but is usually written "Foerster" even in most German sources where 'ö' is otherwise used in the text.A native of Grünberg, Silesia, he worked as...

, Gustav Kirchhoff
Gustav Kirchhoff
Gustav Robert Kirchhoff was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects...

 and Arthur Auwers
Arthur Auwers
Georg Friedrich Julius Arthur von Auwers was a German astronomer.Auwers was born in Göttingen, attended the University of Göttingen and worked at the University of Königsberg. He specialized in astrometry, making very precise measurements of stellar positions and motions...

. In 1882 Carl Hermann Vogel
Hermann Carl Vogel
Hermann Carl Vogel was a German astronomer. He was born in Leipzig, Kingdom of Saxony.Vogel pioneered the use of the spectroscope in astronomy...

 was appointed as sole director of the observatory. The main focus of his work was now on stellar astrophysics. He was the first successfully to determine radial velocities of stars photographically and as a result he discovered the spectroscopic binaries.

In 1899 the then-largest refractor
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...

 in the world, Great Refractor
Great refractor
Great refractor refers to a large telescope with a lens, usually the largest refractor at an observatory with an equatorial mount. The preeminence and success of this style in observational astronomy was an era in telescope use in the 19th and early 20th century. Great refractors were large...

 of Potsdam, with lenses of 80 and 50 cm, was manufactured by the firms of Steinheil
Carl August von Steinheil
Carl August von Steinheil was a German physicist, inventor, engineer and astronomer.-Biography:Steinheil was born in Ribeauvillé, Alsace. He studied law in Erlangen since 1821, then astronomy in Göttingen and Königsberg. He continued his studies in astronomy and physics when he started living on...

 and Repsold
Johann Georg Repsold
Johann Georg Repsold was a German astronomer.He joined the fire brigade of Hamburg in 1799. In 1802 he began building a private observatory, and collaborated in astronomical observations with Heinrich Christian Schumacher. However the observatory was destroyed in the Napoleonic Wars in 1811...

, and mounted in a 24 m dome. It was inaugurated in a great celebration by the German emperor, Wilhelm II. Although it did not realize all the hopes astronomers had for it, nevertheless two important discoveries should be mentioned: the interstellar calcium lines in the spectrum of the spectroscopic binary Delta Orionis
Delta Orionis
Delta Orionis , traditionally known as Mintaka , is a star some 900 light years distant in the constellation Orion. Together with Zeta Orionis and Epsilon Orionis , the three stars make up the belt of Orion, known by many names across many ancient cultures...

 by Johannes Hartmann
Johannes Franz Hartmann
Johannes Franz Hartmann was a German physicist and astronomer. In 1904, while studying the spectroscopy of Delta Orionis he noticed that most of the spectrum had a shift, except the calcium lines, which he interpreted as indicating the presence of interstellar medium-External links:*...

 in 1904 and the presence of stellar calcium emission lines — a hint of stellar surface activity — by Gustav Eberhard
Gustav Eberhard
Gustav E. Eberhard German astrophysicist.Eberhard published numerous investigations on spectroscopy and on photographic photogrametry....

 and Hans Ludendorff
Hans Ludendorff
Friedrich Wilhelm Hans Ludendorff was a German astronomer and astrophysicist. He was the younger brother of General Erich Ludendorff....

 about 1900.

Ten years later one of the most famous astrophysicists of this century, Karl Schwarzschild
Karl Schwarzschild
Karl Schwarzschild was a German physicist. He is also the father of astrophysicist Martin Schwarzschild.He is best known for providing the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished...

, became director of the observatory. In only a few years of work (by 1916 he had died from a chronic illness) he had made fundamental contributions in astrophysics and to General Relativity Theory
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...

. Only a few weeks after the theory's publication by Einstein, Schwarzschild found the first solution of the Einstein equations
Einstein field equations
The Einstein field equations or Einstein's equations are a set of ten equations in Albert Einstein's general theory of relativity which describe the fundamental interaction of gravitation as a result of spacetime being curved by matter and energy...

, which is now named after him as the "Schwarzschild solution
Schwarzschild metric
In Einstein's theory of general relativity, the Schwarzschild solution describes the gravitational field outside a spherical, uncharged, non-rotating mass such as a star, planet, or black hole. It is also a good approximation to the gravitational field of a slowly rotating body like the Earth or...

" and which is of fundamental importance for the theory of black holes.

There exist further close links between the AOP and Einstein's Relativity Theory. In 1881 Albert A. Michelson
Albert Abraham Michelson
Albert Abraham Michelson was an American physicist known for his work on the measurement of the speed of light and especially for the Michelson-Morley experiment. In 1907 he received the Nobel Prize in Physics...

 first performed his interferometer experiments in the cellar of the main building of the AOP, that were to disprove the movement of the Earth through a hypothetical aether
Luminiferous aether
In the late 19th century, luminiferous aether or ether, meaning light-bearing aether, was the term used to describe a medium for the propagation of light....

. His negative results were fundamentally reconciled only through Einstein's Special Relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...

 theory of 1905.

To prove the gravitational redshift
Gravitational redshift
In astrophysics, gravitational redshift or Einstein shift describes light or other forms of electromagnetic radiation of certain wavelengths that originate from a source that is in a region of a stronger gravitational field that appear to be of longer wavelength, or redshifted, when seen or...

 of spectral lines of the Sun — an effect proposed by Einstein's theory of General Relativity — was the aim of a solar tower telescope
Einstein Tower
The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

, which was built from 1921 to 1924 at the instigation of Erwin Finlay-Freundlich
Erwin Finlay-Freundlich
Erwin Finlay-Freundlich was a German astronomer, a pupil of Felix Klein. He was born in Biebrich, Germany. Freundlich was a working associate of Albert Einstein and introduced experiments for which the general theory of relativity could be tested by astronomical observations based on the...

. Though at that time it was not yet technically possible to measure the gravitational redshift, important developments in solar and plasma physics were started here and the architect, Erich Mendelsohn
Erich Mendelsohn
Erich Mendelsohn was a Jewish German architect, known for his expressionist architecture in the 1920s, as well as for developing a dynamic functionalism in his projects for department stores and cinemas.-Early life:...

, created with this peculiarly expressionistic tower a unique scientific building.

Besides the work of Schwarzschild, in the following decades important observational programmes such as the Potsdamer Photometrische Durchmusterung and the outstanding investigations of Walter Grotrian
Walter Grotrian
Walter Robert Wilhelm Grotrian was a German astronomer and astrophysicist.Grotrian studied the emission line from the solar corona in the green region of the spectrum; this emission line could not be attributed to any known chemical element and was thought to be a new element...

 on the solar corona
Corona
A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...

 found recognition all over the world.

Relocation of the Berlin Observatory to Babelsberg

At the end of the 19th century the Berlin Observatory
Berlin Observatory
The Berlin Observatory is a series of observatories and related organizations in and around the city of Berlin in Germany, starting from the 18th century...

, originally built outside the border of the town, was enclosed by blocks of flats, so scientific observations were almost impossible. Therefore, Foerster proposed the removal of the observatory to a place outside Berlin with better observational conditions. In 1904 he appointed Karl Hermann Struve
Hermann Struve
Karl Hermann Struve was a Russian astronomer. In Russian, his name is sometimes given as German Ottovich Struve or German Ottonovich Struve ....

, former director of the observatory of Königsberg, as his successor to realize this project.

After test observations by Paul Guthnick
Paul Guthnick
Paul Guthnick was a German astronomer.Born in Hitdorf am Rhein, he worked from 1901 at the Royal Observatory of Berlin. He studied variable stars and studied Mira . As Berlin expanded, it became less possible to conduct astronomical observations there and Guthnick used, from 1906 onwards, the...

 in the summer of 1906 a new site was found on a hill in the eastern part of the Royal Park of Babelsberg
Potsdam-Babelsberg
Babelsberg is the largest district of the Brandenburg capital Potsdam in Germany. The affluent neighbourhood named after a small hill on the Havel river is famous for Babelsberg Palace and Park, part of the Palaces and Parks of Potsdam and Berlin UNESCO World Heritage Site, as well as for Studio...

. The ground was placed at the observatory's disposal by the crown free of charge. The costs of the new buildings and the new instruments amounted to 1.5 million Goldmark and could be covered by selling the landed property of the Berlin Observatory. The old observatory built by Schinkel was pulled down later. In June 1911 the construction of a new observatory began in Babelsberg and on 2 August 1913 the removal from Berlin to Babelsberg was complete.

The first new instruments were delivered in the spring of 1914. The 65 cm refractor
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...

 — the first big astronomical instrument manufactured by the famous enterprise of Carl Zeiss Jena — was mounted in 1915, whereas the completion of the 122 cm reflector telescope was delayed until 1924 by the First World War. Struve died in 1920 from an accident, and his successor was Paul Guthnick
Paul Guthnick
Paul Guthnick was a German astronomer.Born in Hitdorf am Rhein, he worked from 1901 at the Royal Observatory of Berlin. He studied variable stars and studied Mira . As Berlin expanded, it became less possible to conduct astronomical observations there and Guthnick used, from 1906 onwards, the...

, who introduced in 1913 photoelectric photometry into astronomy as the first objective method of measuring the brightness of stars. When the 122 cm telescope (at this time the second largest in the world) was finished, the Babelsberg Observatory was the best-equipped observatory of Europe.

The development of the photoelectric method for investigating weakly variable stars and spectroscopic investigations with the 122 cm telescope made the Babelsberg observatory well-known beyond Europe, too.

At the beginning of 1931 the Sonneberg Observatory
Sonneberg Observatory
Sternwarte Sonneberg is an astronomical observatory and was formerly an institute of the Academy of Science in the German Democratic Republic. It was founded in 1925 by Cuno Hoffmeister and is located in Sonneberg, Thuringia, Germany. Sonnenberg Observatory has one of the world's largest...

 founded by Cuno Hoffmeister
Cuno Hoffmeister
Cuno Hoffmeister was a German astronomerand founder of Sonneberg Observatory.Born in Sonneberg in 1892, Hoffmeister obtained his first telescope in 1905 and became an avid amateur astronomer. After his father lost most of his money in 1914, Hoffmeister had to leave school in 1916 to start an...

 was attached to the Babelsberg Observatory. For more than 60 years a photographic sky survey was carried out, which represents the second largest archive of astronomical photographic plates. This archive and the discovery and investigation of variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

s popularized the name Sonneberg all over the astronomical world.

With the beginning of the fascist regime, the fortunes of astronomy in Potsdam as well as in Babelsberg started to decline. The banishment of Jewish co-workers played an essential role in this process. The beginning of the Second World War practically marked the cessation of astronomical research.

Developments after the Second World War

The new start after the war was very difficult. In Potsdam the Einstein Tower
Einstein Tower
The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

 had suffered heavy damage by bombs, in Babelsberg
Potsdam-Babelsberg
Babelsberg is the largest district of the Brandenburg capital Potsdam in Germany. The affluent neighbourhood named after a small hill on the Havel river is famous for Babelsberg Palace and Park, part of the Palaces and Parks of Potsdam and Berlin UNESCO World Heritage Site, as well as for Studio...

 valuable instruments, among them the 122 cm telescope (whose former building now houses the AIP library), were dismounted and removed to the Soviet Union as war reparations. Now the 122 cm telescope is in the Crimean Astrophysical Observatory
Crimean Astrophysical Observatory
The Crimean Astrophysical Observatory is located in Ukraine. CrAO has been publishing the Bulletin of the Crimean Astrophysical Observatory since 1947, in English since 1977. The observatory facilities are located near the settlement of Nauchny since the mid-1950s; before that, they were further...

.

In January 1947 the German Academy of Sciences took the AOP and the Babelsberg Observatory under its administration, but it was not until the beginning of the 1950s before astronomical research started anew.

AOP director Hans Kienle took over the editorial duties of the professional journal Astronomical Notes
Astronomische Nachrichten
Astronomische Nachrichten , one of the first international journals in the field of astronomy, was founded in 1821 by the German astronomer Heinrich Christian Schumacher. It claims to be the oldest astronomical journal in the world that is still being published...

 (German: Astronomische Nachrichten
Astronomische Nachrichten
Astronomische Nachrichten , one of the first international journals in the field of astronomy, was founded in 1821 by the German astronomer Heinrich Christian Schumacher. It claims to be the oldest astronomical journal in the world that is still being published...

), which is to this day edited at the AIP and moreover the oldest professional journal for astronomy.

In June 1954 the Observatory for Solar Radio Astronomy (OSRA) in Tremsdorf (17 km southeast of Potsdam) began its work as a part of the AOP. Its history started in 1896: after the discovery of the radio waves by Heinrich Hertz in 1888, Johannes Wilsing
Johannes Wilsing
Johannes Wilsing was a German astronomer.He was born in Berlin, where he was educated in addition to Göttingen. In 1880 he was awarded his Ph.D...

 and Julius Scheiner
Julius Scheiner
Julius Scheiner was a German astronomer, born in Cologne and educated at Bonn. He became assistant at the astrophysical observatory in Potsdam in 1887 and its observer in chief in 1898, three years after his appointment to the chair of astrophysics in the University of Berlin...

, fellows of the AOP, tried to detect radio emission from the Sun. They did not succeed, because of the low sensitivity of their equipment. After the Second World War Herbert Daene started once again to attempt radio observations of the Sun in Babelsberg which were continued in Tremsdorf.

In October 1960 the 2 m telescope built by Carl Zeiss Jena was inaugurated in the Tautenburg
Tautenburg
Tautenburg, a municipality in the Saale-Holzland district in Thuringia in Germany, houses the Karl Schwarzschild Observatory....

 Forest near Jena and the new Karl Schwarzschild Observatory
Karl Schwarzschild Observatory
The Karl-Schwarzschild-Observatorium is an astronomical observatory owned and operated by the institute of Thüringer Landessternwarte ’Karl Schwarzschild’ Tautenburg. In 1992 it was acquired by the state of Thuringia...

 was founded. The Schmidt variant of this telescope is to this day the largest astronomical wide-field camera in the world and it was the main observational instrument of the astronomers of the GDR.

In 1969 the four East-German astronomical institutes, Astrophysical Observatory Potsdam, Babelsberg Observatory, the Thuringian Sonneberg Observatory
Sonneberg Observatory
Sternwarte Sonneberg is an astronomical observatory and was formerly an institute of the Academy of Science in the German Democratic Republic. It was founded in 1925 by Cuno Hoffmeister and is located in Sonneberg, Thuringia, Germany. Sonnenberg Observatory has one of the world's largest...

, and Karl Schwarzschild Observatory
Karl Schwarzschild Observatory
The Karl-Schwarzschild-Observatorium is an astronomical observatory owned and operated by the institute of Thüringer Landessternwarte ’Karl Schwarzschild’ Tautenburg. In 1992 it was acquired by the state of Thuringia...

 Tautenburg
Tautenburg
Tautenburg, a municipality in the Saale-Holzland district in Thuringia in Germany, houses the Karl Schwarzschild Observatory....

, were joined in the course of academy reform to the Central Institute of Astrophysics of the Academy of Sciences of the GDR. The solar observatory Einstein Tower
Einstein Tower
The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

 and Observatory for Solar Radio Astronomy were affiliated later.

One part of the scientific activities concerned cosmic magnetic fields and cosmic dynamos, phenomena of turbulence, magnetic and eruptive processes on the Sun, explosive energy dissipation processes in plasmas, variable stars and stellar activity. Another part was directed to the early phases of cosmic evolution and the origin of structures in the Universe, large-scale structures up to those of supercluster
Supercluster
Superclusters are large groups of smaller galaxy groups and clusters and are among the largest known structures of the cosmos. They are so large that they are not gravitationally bound and, consequently, partake in the Hubble expansion.-Existence:...

s and to active galaxies
Active galactic nucleus
An active galactic nucleus is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum. Such excess emission has been observed in the radio, infrared, optical, ultra-violet, X-ray and...

. In this connection special methods of image processing have been developed. In addition, investigations in astrometry
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...

 have also been performed.

The scientific work of the Central Institute for Astrophysics suffered strongly from the isolation of the GDR from the western world. It was very difficult to come into contact with western colleagues. After the autumn 1989 fall of the Berlin Wall, new possibilities at once arose.

Reunification and the founding of the AIP

On the basis of the prescriptions of the Unification Agreement for the Academy of Sciences
German Academy of Sciences Berlin
The German Academy of Sciences at Berlin , later renamed Academy of Sciences of the German Democratic Republic was the most important research institution of East Germany.The academy was founded in 1946 by the Soviet Military Administration in Germany to continue the long tradition of the...

 of the GDR, the Central Institute of Astrophysics was dissolved on 31 December 1991. On the recommendation of the Science Council on 1 January 1992 the Astrophysical Institute Potsdam, with a greatly reduced staff, was founded. It occupies the former Babelsberg Observatory site in Potsdam-Babelsberg
Potsdam-Babelsberg
Babelsberg is the largest district of the Brandenburg capital Potsdam in Germany. The affluent neighbourhood named after a small hill on the Havel river is famous for Babelsberg Palace and Park, part of the Palaces and Parks of Potsdam and Berlin UNESCO World Heritage Site, as well as for Studio...

.

The Sonneberg Observatory
Sonneberg Observatory
Sternwarte Sonneberg is an astronomical observatory and was formerly an institute of the Academy of Science in the German Democratic Republic. It was founded in 1925 by Cuno Hoffmeister and is located in Sonneberg, Thuringia, Germany. Sonnenberg Observatory has one of the world's largest...

 and the Karl Schwarzschild Observatory
Karl Schwarzschild Observatory
The Karl-Schwarzschild-Observatorium is an astronomical observatory owned and operated by the institute of Thüringer Landessternwarte ’Karl Schwarzschild’ Tautenburg. In 1992 it was acquired by the state of Thuringia...

 are no longer affiliated with the AIP, but the AIP still operates the Observatory for Solar Rado Astronomy (OSRA) in Tremsdorf and maintains the Great Refractor and Einstein Tower
Einstein Tower
The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

 at Telegrafenberg.

Since then, the AIP has broadened its research areas, initiated several new technical projects, and participates in several large international research projects (see below).

On April 15, 2011, the name of the AIP was changed to "Leibniz Institute for Astrophysics Potsdam", to
emphasize the affiliation of the institute with the Leibniz Association. The institute retains the abbreviation
"AIP", as well as the "aip.de" Internet domain.

Main Research Areas

  • Magnetohydrodynamics
    Magnetohydrodynamics
    Magnetohydrodynamics is an academic discipline which studies the dynamics of electrically conducting fluids. Examples of such fluids include plasmas, liquid metals, and salt water or electrolytes...

     (MHD): Magnetic fields and turbulence in stars, accretion disks and galaxies; computer simulations ao dynamos, magnetic instabilities and magnetic convection

  • Solar physics
    Solar physics
    For the physics journal, see Solar Physics Solar physics is the study of our Sun. It is a branch of astrophysics that specializes in exploiting and explaining the detailed measurements that are possible only for our closest star...

    : Observation of sunspots and of solar magnetic field with spectro-polarimetry; Helioseismology
    Helioseismology
    Helioseismology is the study of the propagation of wave oscillations, particularly acoustic pressure waves, in the Sun. Unlike seismic waves on Earth, solar waves have practically no shear component . Solar pressure waves are believed to be generated by the turbulence in the convection zone near...

     and hydrodynamic numerical models; Study of coronal plasma processes by means of radio astronomy; Operation of the Observatory for Solar Radio Astronomy (OSRA) in Tremsdorf, with four radio antennas in different frequency bands from 40 MHz to 800 MHz

  • Stellar physics
    Stellar physics
    Stellar physics, is a term coined for the research concerning the formation, evolution, interior and the atmospheres of stars. The understanding of the birth and death of stars requires the application of almost all branches of modern physics...

    : Numerical simulations of convection in stellar atmospheres, determination of stellar surface parameters and chemical abundances, winds and dust shells of red giants; Doppler tomography of stellar surface structures, development of robotic telescopes, as well as simulation of magnetic flux tubes

  • Star formation and the interstellar medium
    Interstellar medium
    In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...

    : Brown dwarfs and low-mass stars, circumstellar disks, Origin of double and multiple-star systems

  • Galaxies
    Galaxy
    A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...

     and quasar
    Quasar
    A quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...

    s: Mother galaxies and surroundings of quasars, development of quasars and active galactic cores, structure and the story of the origin of the Milky Way, numerical computer simulations of the origin and development of galaxies

  • Cosmology
    Cosmology
    Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

    : Numerical simulation of the formation of large-scale structures. Semi-analytic models of galaxy formation and evolution. Predictions for future large observational surveys.

Large Binocular Telescope

The Large Binocular Telescope
Large Binocular Telescope
Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

 (LBT) is a new telescope on Mt. Grahams in Arizona. The LBT consists of 2 huge 8.4 m telescopes on a common mount. With their 110 square meter area, the LBT is the largest telescope in the world on a single mount, only surpassed by the combined VLTs and Kecks.

RAVE

The Radial Velocity Experiment measures until 2010 the radial velocities and elemental abundances of a million stars, predominantly in the southern celestial hemisphere. The 6dF multi-object spectrograph
Spectrograph
A spectrograph is an instrument that separates an incoming wave into a frequency spectrum. There are several kinds of machines referred to as spectrographs, depending on the precise nature of the waves...

 on the 1.2 m UK Schmidt telescope of the Anglo-Australian Observatory
Anglo-Australian Observatory
The Australian Astronomical Observatory , formerly the Anglo-Australian Observatory, is an optical/near-infrared astronomy observatory with its headquarters in suburban Sydney, Australia...

 will be applied for this purpose.

Sloan Digital Sky Survey

The Sloan Digital Sky Survey
Sloan Digital Sky Survey
The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...

 (SDSS) will investigate in detail a quarter of the whole sky and determine the position and absolute brightness of more than 100 million sky objects. Besides that, the distances of more than a million galaxies and quasars will be estimated. With the help of this study, astronomers will be able to assess the distribution of large-scale structures in the Universe. This can provide hints about the story of the development of the Universe.

LOFAR (LOw Frequency ARray)

LOFAR
LOFAR
LOFAR is the Low Frequency Array for radio astronomy, built by the Netherlands astronomical foundation ASTRON and operated by ASTRON's radio observatory....

 is a European radio interferometer, that measures radio waves with many individual antennas in different places which it combines to a single signal. One of these international LOFAR
LOFAR
LOFAR is the Low Frequency Array for radio astronomy, built by the Netherlands astronomical foundation ASTRON and operated by ASTRON's radio observatory....

 stations will be presently constructed by the AIP in Bornim by Potsdam.

Virtual Observatory

The German Astrophysical Virtual Observatory (GAVO) is an e-Science
E-Science
E-Science is computationally intensive science that is carried out in highly distributed network environments, or science that uses immense data sets that require grid computing; the term sometimes includes technologies that enable distributed collaboration, such as the Access Grid...

 project, that creates a virtual observation platform to support modern astrophysical research in Germany. It is the German contribution to international efforts to establish a general Virtual Observatory
Virtual Observatory
Virtual observatory is a collection of interoperating data archives and software tools which utilize the internet to form a scientific research environment in which astronomical research programs can be conducted....

. GAVO enables standardized access to German and international data archives.

GREGOR

GREGOR is a 1.5 m telescope for solar research of the Teide Observatory
Teide Observatory
The Observatorio del Teide is an astronomical observatory on Tenerife operated by the Instituto de Astrofísica de Canarias. Opened in 1964, it became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical...

 on Tenerife. It is a new type of solar telescope, which supersedes the previous 45 cm Gregory-Coudé telescope. GREGOR is equipped with adaptive optics
Adaptive optics
Adaptive optics is a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, and in retinal imaging systems to reduce the...

 and will achieve a resolution of 70 km of the Sun's surface. The investigation of these small structures is important for the understanding of the underlying processes of the interaction of magnetic fields with plasma turbulence on the Sun. The development of the Gregor telescope will be led by the Kiepenheuer-Institut für Sonnenphysik (KIS)
with the participation of several institutes.

AGWs of the Large Binocular Telescope

The AIP is a partner in the LBT Consortium (LBTC) and contributes financially and materially in the construction of the Large Binocular Telescope
Large Binocular Telescope
Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

. This entails both the development and the fabrication of the optics and the mechanical and electronic components as well as the development of the software for the acquisition, guiding and wavefront sensing units (AGWs). The AGW units are essential components of the telescope and indispensable for the adaptive optics
Adaptive optics
Adaptive optics is a technology used to improve the performance of optical systems by reducing the effect of wavefront distortions. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, and in retinal imaging systems to reduce the...

.

Multi Unit Spectroscopic Explorer

The Multi Unit Spectroscopic Explorer (MUSE) is an instrument of the second generation for the VLT
VLT
VLT may stand for:* Very Large Telescope, a system of four large optical telescopes organized in an array formation, located in northern Chile...

 of the ESO
European Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...

. MUSE is optimized for the observation of normal galaxies out to very high redshift. It will furthermore deliver detailed studies of nearby normal, interacting, and starburst galaxies.

Potsdam Echelle Polarimetric & Spectroscopic Instrument (PEPSI)

PEPSI is a high-resolution spectrograph
Spectrograph
A spectrograph is an instrument that separates an incoming wave into a frequency spectrum. There are several kinds of machines referred to as spectrographs, depending on the precise nature of the waves...

 for the LBT
Large Binocular Telescope
Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

. It will enable the simultaneous observation of circularly and linearly polarized light with high spectral and temporal resolution. The spectrograph is situated in a temperature- and pressure-stabilized room within the telescope column. The light will be conducted by fiber optics from the telescope to the spectrograph.

STELLA

STELLA is a robotic observatory that consists of two 1.2 m telescopes. It is a long-term project to observe indicators of stellar activity of Sun-like stars. The operation occurs unattended — the telescopes decide the appropriate observation strategy automatically.

Observatory for Solar Radio Astronomy (OSRA)

The robotic radio observatory OSRA will record radio emissions of the Sun's corona with four different four antennas in the frequency bands 40–100 MHz, 100–170 MHz, 200–400 MHz and 400–800 MHz. The antennas follow the Sun automatically.

Telescopes and Collaborations

  • Einstein Tower
    Einstein Tower
    The Einstein Tower is an astrophysical observatory in the Albert Einstein Science Park in Potsdam, Germany built by Erich Mendelsohn. It was built on the summit of the Potsdam Telegraphenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich...

     solar telescope
  • Great Refractor at Telegrafenberg
  • GREGOR solar telescope, collaboration with KIS
  • Large Binocular Telescope
    Large Binocular Telescope
    Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

  • Meridian Circle
    Meridian circle
    The meridian circle, transit circle, or transit telescope is an instrument for observing the time of stars passing the meridian, at the same time measuring its angular distance from the zenith...

  • OSRA Solar Radio Observatory in Tremsdorf
  • RoboTel robotic telescope
  • STELLA robotic telescope
  • Vacuum Tower Telescope
    Vacuum Tower Telescope
    For the vacuum tower telescope at Sacramento Peak, see Richard B. Dunn Solar Telescope.The Vacuum Tower Telescope is an evacuated-optics solar telescope located at the Teide Observatory on Tenerife in the Canary Islands. It is operated by the Kiepenheuer-Institut für Sonnenphysik ..It has a ...

    VTT, collaboration with KIS
  • Zeiss 70 cm reflector telescope
  • Zeiss 50 cm reflector telescope
  • Zeiss refractor telescope

External links

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