Hans Oswald Rosenberg (18 May 1879 – 26 July 1940) was a German astronomer. He worked in the

University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-Wü ...

before losing his job in Nazi Germany for having Jewish descent. He then moved to the United States of America and then to Turkey. He studied correlations between spectra and magnitude and produced a precursor of the Hertzsprung-Russell Diagram in 1910 using stars at similar distances within the

Pleiades cluster The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...

. Rosenberg was born in Berlin to banker Hermann and wife Else née Dohm.

Hedwig Pringsheim Hedwig Pringsheim (born Gertrud Hedwig Anna Dohm; 13 July 1855 – 27 July 1942) was a German actress. Born in Berlin, she was the daughter of Ernst Dohm and Hedwig Dohm-Schleh, who were Jewish converts to Christianity. She married Alfred Pringsh ...

(1855–1942) was a maternal aunt who had married the mathematician

Alfred Pringsheim Alfred Pringsheim (2 September 1850 – 25 June 1941) was a German mathematician and patron of the arts. He was born in Ohlau, Prussian Silesia (now Oława, Poland) and died in Zürich, Switzerland. Family and academic career Pringsheim came ...

. After studies at the

Friedrich Wilhelm Gymnasium The Friedrich Wilhelm Gymnasium (or Friedrich-Wilhelms-Gymnasium) was a secondary school ( ''Gymnasium'') in Berlin. History The school originated from a Realschule founded by the Pietist Johann Julius Hecker in 1747, the first secondary school ...

in Berlin, he went to study science in Munich (where Pringsheim was a professor) and Berlin followed by a doctorate at the

University of Strasbourg The University of Strasbourg (french: Université de Strasbourg, Unistra) is a public research university located in Strasbourg, Alsace, France, with over 52,000 students and 3,300 researchers. The French university traces its history to the ea ...

under Ernst Becker studying the variable star χ Cygni. He then worked as an assistant to

Karl Schwarzschild Karl Schwarzschild (; 9 October 1873 – 11 May 1916) was a German physicist and astronomer. Schwarzschild provided the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-r ...

at the

. He became a head of the observatory there apart from teaching. He began to experiment in photometry and the measurement of star brightness using photoelectric measurements. In 1926 he became a professor at the

University of Kiel Kiel University, officially the Christian-Albrecht University of Kiel, (german: Christian-Albrechts-Universität zu Kiel, abbreviated CAU, known informally as Christiana Albertina) is a university in the city of Kiel, Germany. It was founded in ...

. He went on expeditions to track total solar eclipses from Thailand and Sweden. With the rise of Nazi power, he was initially allowed to teach even though he had Jewish ancestry (the family had converted to Protestants), since he had served in World War I; however, this changed in 1933 when he was forced to take leave of absence. In 1934 he was allowed to travel to the United States where he began to teach at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...

and work at the

Yerkes Observatory Yerkes Observatory ( ) is an astronomical observatory located in Williams Bay, Wisconsin, United States. The observatory was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 to 2018. Owne ...

with

Otto Struve Otto Struve (August 12, 1897 – April 6, 1963) was a Russian-American astronomer of Baltic German origins. In Russian, his name is sometimes given as Otto Lyudvigovich Struve (Отто Людвигович Струве); however, he spent most o ...

. His position at Kiel was officially terminated in May 1935. In 1938 he emigrated to Turkey where he joined the

Istanbul University , image = Istanbul_University_logo.svg , image_size = 200px , latin_name = Universitas Istanbulensis , motto = tr, Tarihten Geleceğe Bilim Köprüsü , mottoeng = Science Bridge from Past to the Future , established = 1453 1846 1933 ...

, succeeding

Erwin Freundlich Erwin Finlay-Freundlich FRSE FRAS (; 29 May 1885 – 24 July 1964) was a German astronomer, a pupil of Felix Klein. Freundlich was a working associate of Albert Einstein and introduced experiments for which the general theory of relativity coul ...

. He worked in Istanbul until his death from heat stroke. Rosenberg was married to Verena née Borchardt (1882-1954), youngest sister of the poet Rudolf Borchardt. They had three sons and two daughters including Eva Maria Borer (1905-1987) who became a journalist.

References

External links

The First Hertzsprung-Russell Diagram by Michael E. Marotta
{{DEFAULTSORT:Rosenberg, Hans Oswald 1879 births 1940 deaths German astronomers People from Berlin Academic staff of the University of Kiel German expatriates in Turkey Expatriate academics in Turkey Academic staff of Istanbul University