Hamburg Observatory


Hamburg Observatory is an astronomical observatory located in the Bergedorf borough of the city of Hamburg in northern Germany. It is owned and operated by the University of Hamburg, Germany since 1968, although it was founded in 1825 by the City of Hamburg and moved to its present location in 1912. It has operated telescopes at Bergedorf, at two previous locations in Hamburg, at other observatories around the world, and it has also supported space missions.
The largest near-Earth object was discovered at this Observatory by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg on 23 October 1924. That asteroid, 1036 Ganymed is about 20 miles in diameter.
The Hamburg 1-meter reflector telescope was one of the biggest telescopes in Europe at that time, and by some measures the fourth largest in the World. The Observatory also has an old style Great Refractor, a long telescope with a lens with a tube focal length of 9 meters, and there is also a smaller one from the 19th century that has survived. Another historical item of significance is the first and original Schmidt telescope, a type noted for its wide-field views.
Among its achievements, the director of the Observatory won the 1854 Gold Medal of the Royal Astronomical Society for a 1852 star catalog.

History

Stintfang (1802–1811)

The precursor of Hamburg Observatory was a quasi-private observatory by Johann Georg Repsold built in 1802, originally located at the Stintfang in Hamburg. It was built in the city with permission of the Congress. It started in 1803, and had a meridian circle built by Repsold. However, it was destroyed in 1811 by a war. Repsold, Reinke, and J.C. von Hess submitted a proposal to Hamburg for city observatory that same year, to rebuild.

Millerntor (1825–1906)

Funding for a new Observatory was approved in August 1821, on the condition J. G. Repsold built the instruments. The new observatory was completed in 1825 next to the Millerntor. However, in 1830 Repsold died while fighting a fire and the City of Hamburg voted to take over and continue running the observatory in 1833. First director became Charles Rümker who had accompanied Thomas Brisbane to build the first Australian observatory at Parramatta. Christian August Friedrich Peters became assistant director in 1834. In 1856 Rümker's son George became director of the observatory.
In 1854 Carl Rumaker won the Gold Medal from the Royal Society for year, for his 1852 Star catalog, which had the positions of 12000 stars.
In 1876 funding was received for 'The Equatorial', a refractor; it was later moved to Bergedorf.
After the move to Bergedorf, the site was partially demolished and rebuilt into the Museum of Hamburg History.

Bergedorf (1912–present)

Because of the increasing light pollution, in 1906 it was decided to move the observatory to Bergedorf. In 1909 the first instruments were moved there, and in 1912 the new observatory was officially dedicated.
One of the overall design elements of Bergeforf, is that each instrument was placed in its own building, rather than integrated in one large building.
Two new instruments for the Bergedorf location were the 60 cm aperture Great Refractor by Reposold, and Meridian Circle. One unique feature of Hamburg Great Refractor is an Iris control that allows the aperture to be adjusted from 5 to 60 cm. Two lens were produced by Steinheil, one for photography and another for visual observing, both delivered in the early 1910s.
The European Southern Observatory was founded at Bergedorf in 1962. That organization put a lot telescopes in the southern hemisphere, which is not as viewable from northern part of Earth.
The Hamburg 1 m Reflector was the world's fourth largest reflector when it began operations in 1911. Catalogs include the AGK3-Sternkatalog
In 1968 the observatory became part of Hamburg University. In 1979 a small museum to Bernard Schmidt was inaugurated. In 2012, 100 years at Bergedorf was celebrated.
In 2019, the Great Refractor building was re-open in June after it was modernized.

1-meter reflector

The 1 meter reflector at Hamburg Observatory was the largest by aperture in Germany, and one of the largest in Europe, and was also among the largest telescopes of any type in the World at that time.
;Largest telescopes
Name/ObservatoryAperture
cm 		TypeLocationExtant or Active
Harvard 60-inch Reflector1.524 m reflector – glassHarvard College Observatory, USA1905–1931
Hale 60-Inch Telescope1.524 m reflector – glassMt. Wilson Observatory; California1908
Great Melbourne Telescope122 cmreflector – metalMelbourne Observatory, Australia1878
Yerkes Observatory102 cm achromatWilliams Bay, Wisconsin, USA1897-2018
Hamburg 1 Meter Reflector100 cm reflector – glassHamburg, Germany1911
James Lick telescope, Lick Observatory91 cm achromatMount Hamilton, California, USA1888
Crossley Reflector 91.4 cmreflector – glassMount Hamilton, California, USA1896
Grande Lunette, Paris Observatory83 cm + 62 cm
achromat x2Meudon, France1891
Potsdam Großer Refraktor
Astrophysical Observatory Potsdam		80 cm + 50 cm
achromat x2Potsdam, Deutsches Kaiserreich1899
Focault 80 cm, Marseille Observatory80 cm reflector-glassMarseille, France1862–1965
Grand Lunette Biscoffscheim, Nice Observatory77 cm achromatNice, France1886

Note that the prevailing glass mirror technology at this time was silver coated glass, not vapor deposited aluminum which did not debut until several decades later. Speculum metal mirror reflected something like 2/3 of the light, and the lens telescopes were popular for their virtues but had enormous and expensive domes due to their long focal length

Telescopes

;Telescopes

People of Hamburg Observatory

Directors of the Observatory:
Bernhard Schmidt, inventor of the Schmidt camera worked at the Observatory including making telescopes, instruments, and observations starting in 1916. Walter Baade successfully petitioned the Hamburg senate to have Schmidt camera installed in 1937, and it was completed in 1954 after work restarted on in 1951 after being interrupted by WWII. Walter Baade also succeeded in having a Schmidt camera built at Palomar Observatory in California.
In 1928, Kasimir Graff made many observations at Hamburg until he left for the Vienna Observatory.