Rudolf Straubel

Rudolf Straubel (* June 16, 1864 in Kleinschmalkalden; † December 2, 1943 in Jena) was a German physicist, scientist, top-manager, inventor and sponsor of community. He was the successor to Ernst Abbe and managing director of Carl Zeiss in Jena from 1903 to 1933.

Childhood and school
Rudolf Straubel was born in 1864 as the son of the pastor Carl Julius Straubel and his wife Emilie Natalie née Sterzing in Kleinschmalkalden. He had four other siblings. He spent his childhood and school in Schönau vor dem Walde (Thuringian Forest). From 1876 to 1882 he attended the Ernestinum in Gotha, and in 1884 he graduated from the 'Gymnasium Casimirianum Coburg' in Coburg (upper Franconia).

Studies
After graduating from high school, he initially served as a one-year volunteer in the Jena Royal Fusilier Battalion. His main subjects at university were mathematics and physics. His teachers at the University of Jena included Ernst Abbe and Gottlob Frege. From 1885 to 1886, Straubel studied in Berlin under Weierstrass, Kronecker and Helmholtz. In 1886 he continued his studies in Jena and completed them in 1888 with a dissertation entitled "On the calculation of Fraunhofer's diffraction phenomena with special consideration of the theory of diffraction in the heliometer". Ernst Abbe had inspired him to write this topic.

Physicist in Jena
In April 1889, Rudolf Straubel took on an assistant position at the University of Jena. In 1893 he qualified as a professor: “Theory of the diffraction phenomena of circular, non-spherical waves”. In 1997, Straubel was appointed associate professor. He taught the following courses:
 * Physical chemistry
 * Physical colloquium
 * Mathematical geography
 * Geometric optics and theory of optical instruments
 * Electromagnetic wave theory
 * Electromagnetic optics
 * Crystal optics

Geophysics
One of the consequences of the "German Geographers' Day" conference held in Jena in 1897 was the establishment of a "seismic station" under the direction of Rudolf Straubel. Rudolf Straubel improved seismometers with optical recording. Straubel remained head of the seismological station in Schillergäßchen until 1919. The successor to the Jena Seismic Institute was Oskar Hecker.

Managing Director Carl Zeiss Jena 1903–1933
In 1903 Rudolf Straubel became one of the managing directors of Zeiss and Schott, succeeding Ernst Abbe. Felix Jentsch wrote in 1934:

As a result of his high general intelligence and his many years of training in mathematics and physics, but above all as a result of his unusually quick comprehension, which enabled him to find his way around theoretically and practically in the most difficult questions, even if they were quite foreign to pure physics, in the shortest possible time, e.g. in the course of a conversation, Straubel was immediately given tasks that would not otherwise be required of a physics employee. It is characteristic of the circumstances at the time that, as he once told me, his first official task was to draw up an electricity supply contract with the Jena electricity company. Rudolf Straubel played a key role in expanding research and the success of Carl Zeiss in the first half of the 20th century. He resigned in 1933 because he did not want to bow to the pressure of his colleagues in the Zeiss management (Henrichs, Kotthaus, Bauersfeld) and the National Socialists (in the form of Gauleiter Fritz Wächtler) to separate from his Jewish wife Marie Straubel, with whom he had four sons.

Astronomical Department at the Deutsches Museum Munich
In 1903, Oskar von Miller decided to set up a "German Museum of Masterpieces of Science and Technology" in Munich. A connection was sought with Carl Zeiss Jena for a reflector and a refractor telescope (delivered in 1908 and 1909 respectively) and Siegfried Czapski (Carl Zeiss Jena) was elected to the board of the German Museum. After Siegfried Czapski's death in 1907, Rudolf Straubel became a member of the board of the German Museum from 1912 to 1920. In 1913, Rudolf Straubel promised to support the construction of the planetariums (a Copercanic and a Ptolemaic planetarium were planned). The projection planetarium was completed in Jena in 1924 and opened in Munich in 1925.

Spiritual father of the Saale dams
The foundation's operations used a coal-fired power plant on the southern part of the glassworks, but the associated air pollution hindered optical and precision engineering production. In 1912, an AEG generator was constructed as a 10 kV machine for the Burgau hydroelectric power plant. Autumn 1917. Prof. Dr. Rudolf Straubel founded the Hydrotechnical Office (Hydro Office) for the design and construction of hydroelectric power plants. Chief engineer Hans Leicher and engineer Peter, both Swiss citizens, were hired for this purpose. - They returned to their homeland in 1924."

In the following period, the Wisenta, Fernmühle and Conrod power stations were planned and built. After the abdication of Prince Heinrich XXVII the Bleiloch dam was planned and built from 1926 to 1932. The Bleiloch Dam (Thuringia) is therefore not the work of the National Socialists, as they later claimed.

Rudolf Straubel is considered the "father of the Saale Dams".

Jena Glassworks Schott and Co.
After the death of Siegfried Czapki in 1907, Rudolf Straubel was appointed managing director of the Schott & Gen. glassworks. He thus held a dual role as managing director of both Jena foundation companies. Acquired subsidiaries such as Zwieseler and Pirnaer Glaswerke as well as the majority shareholding in the Grünenplaner Glaswerk including the Mitterteicher plant strengthened Schott Jena's position on the market.

Zeiss-Ikon AG Dresden
215 / 5.000 In 1902, Zeiss took over the Jena-based “Palmos Kamera-Werk AG”. In 1909, the “Ica AG” (internationale Camera Aktiengesellschaft) was founded with headquarters in Dresden. Rudolf Straubel remained on the supervisory board until his death in 1943.

National Socialism
The Thuringian Minister of the Interior and Education Wächtler aimed for "a reform of the Marxist and liberalist-tainted Zeiss factory from head to toe" (translated from German). Rudolf Straubel resigned from his position in the foundation's operations on September 30, 1933. Until 1938, his lectures at the University of Jena were shown in the lecture list, then, on orders from Weimar, they were no longer shown. Straubel was "related to Jews"

Family
At a meeting in the house of Felix Auerbach he met Marie Kern, the daughter of a Jewish industrialist and banker from Silesia. They married in Berlin in 1984. In 1902 Marie Straubel became the first chairwoman of the Jena branch of the "Women's Education - Women's Studies" association. She committed suicide in 1944 after receiving a summons to be transported to Theresienstadt. Her husband had died of pancreatic cancer on December 2, 1943. Her sister Therese had already committed suicide before she could be deported to Theresienstadt. She had difficulty walking, which was a main reason why Straubel did not leave Germany with his family. Das Ehepaar hatte 4 Söhne: Heinrich (Heinz) (1895–1970), Werner (1857–1945), Wolfgang (1899–1919) und Harald (1905–1991).

Acknowledgment
The name Rudolf Straubel was largely kept secret in the GDR. He was one of the imperialist corporate leaders, one of the exploiters. Even in the book "Companies without owners. Business decisions of the Carl Zeiss optical workshop from 1889 to 1933", published by De Gruyter Oldenburg in 2023, the name Rudolf Straubel does not appear in the extensive index. In February 2022, a lecture hall in the Abbeanum (lecture hall at university of Jena) was named after him. A street in the southern quarter of Jena was named after him. In 2015, the tomb Straubel-Langer-Zuckerkandl was re-inaugurated at the Jena North Cemetery. In 1924, he became an honorary member of the German Physical Society. In 1930, he became a member of the Leopoldina.

Literature

 * H. Boegehold: Rudolf Straubel zum 70. Geburtstag. In: Die Naturwissenschaften, 22. Jahrgang 1934, S. 421–424.
 * Maximilian Herzberger: The Scientific Work of Constantin Rudolf Straubel. In: Journal of the Optical Society of America, 44. Jahrgang 1954, S. 589–591.
 * F. Jentzsch: Rudolf Straubel zum 70. Geburtstag. In: Zeitschrift für Technische Physik, Jahrgang 1934, Nr. 6.
 * Peter Volz: Tracing paths of history. Rudolf Straubel, Walter Bauersfeld and the projection planetarium. In: Planetarian, 42. Jahrgang 2013, Nr. 4 / 43. Jahrgang 2014, Nr. 1.
 * Reinhard E. Schielicke: Rudolf Straubel 1864–1943. Verlag Vopelius, Jena 2017.
 * Jenaer Jahrbuch zur Technik- und Industriegeschichte, Band 24, Verlag Volpelius Jena, 2021