Rudolf Brandt (astronomer)

Rudolf Brandt (* 1905 ; † 1975 ) was a German optician and research assistant at the Sonneberg observatory in Thuringia. During his many years of activity in Sonneberg , he enriched observational astronomy with several innovations in measurement technology and published several non-fiction books.

As a scientific and technical assistant at the Sonneberg observatory

In 1929 he joined Cuno Hoffmeister's assistant and Kurt Glass's successor at the Sonneberg observatory , which was built in 1925 on Hoffmeister's initiative by the city of Sonneberg on the Erbisbühl high plateau ( Neufang district ). He was soon one of the most prominent employees of the observatory.

Brandt's main area of ​​work was initially the systematic photographic surveillance of the northern sky . It continued the 41 sky fields (8 × 8 ° each) started in 1926 along the plane of the Milky Way and intensified the observation rhythm. This Sonneberg research project with high-quality astro photo plates was the basis for a statistic of variable stars and took place in cooperation with the University Observatory Berlin-Babelsberg under Paul Guthnick .

As early as 1929, the record archive was organized in such a way that a quick check of all desired regions of the sky was possible. As many variables as possible were to be found and monitored on the plates with the blinking comparator , from which the distribution of the different types of stars in the galaxy was later researched. Around 1960, the number of regularly recorded star fields was increased to 100, making the Sonneberg record archive for astronomy a unique treasure trove for discoveries worldwide.

For the Sonneberg sky surveillance , an astrograph with an Ernemann lens with an aperture of 135 mm and a focal length of 240 mm, which Brandt was in charge of, was used. From around 1928/29 onwards, four wide-angle cameras at three German observation locations were involved in this sky surveillance : two cameras in Babelsberg and one each at the observatories in Sonneberg and Bamberg . However, because of the ideal observation conditions in Sonneberg, these four cameras were concentrated in the Sonneberg observatory during the 1930s.

When a research grant from the Notgemeinschaft der Deutschen Wissenschaft for Hoffmeister expired in 1930 and the city of Sonneberg became insolvent in the course of the global economic crisis , the observatory ran into financial difficulties. Finally it was leased to the Prussian state and from 1931 it was run as a department of the Berlin-Babelsberg University Observatory.

Instrumental developments

On his voyage through the Caribbean (1930), Cuno Hoffmeister used a surface photometer developed and built by Brandt to measure the exact course of the brightness of the southern Milky Way and the zodiacal light from on board the ship MS "Magdalena". Brandt then revised the design of the measuring instrument and was able to further increase its accuracy. Hoffmeister used this instrument on his second research voyage in the southern hemisphere, which he completed in 1933 on board the MS "Phrygnia".

After nationalization , larger optical instruments could be developed and put into operation - above all an astrograph with an aperture of 400 mm and a lens focal length of 1600 mm. This increased the range of the photographic star fields from 1938 up to magnitude 17.5.

Brandt soon began an intensive cooperation with Paul Ahnert , who was employed in 1938 and who was to work here for 50 years. a. in the long-term publication of the Himmelsjahr - and later the "Ahnert" yearbook (calendar for star friends) - became visible. In 1940 his boss, Cuno Hoffmeister, became professor of astronomy, but had to submit the observatory to the weather service of the German Air Force . Soon he and four employees were drafted into the Wehrmacht , which Brandt was spared (thanks to the weather service?).

The darkening measures ordered during the Second World War enabled the Sonneberg astronomers again to systematically observe meteors and zodiacal light, especially in the twenties . Limitations in the observation operations resulted from the incorporation of the observatory into the service regime of the militarily organized Reich weather service subordinate to the Air Force. In addition to the astronomical work, there was also meteorological work.

In August 1945 the observatory had to hand over its main instrument, the 400/1600 mm astrograph, two of the sky surveillance cameras and other measuring devices to Soviet observatories as reparations. However, the astronomer Boris Kukarkin, who was entrusted with the dismantling work and in the service of the Soviet Army, made it possible for the record archive to remain at the observatory, which made it possible to continue the research work there.

Brandt's wealth of experience for his books

Brandt gained a wealth of experience which he incorporated into his books and many magazine articles. In 1957 he was able to publish Das Fernrohr des Sternfreundes with Kosmos-Verlag (albeit in the Federal Republic of Germany ) . Despite its only 85 pages, the book formed a much-used basis for visual and photographic astronomy for decades .

As astronomical observation aids for Astro Amateur originate from u Brandt suggestion box. a. a sun prism , which in addition to attenuating the light also ensures that it can hardly heat up thanks to the clever arrangement of the optics, and instructions for various adapters. His tripod adapter for binoculars made of round metal or round wood was replicated thousands of times in the GDR - but also in countries where there was no shortage of goods.

Due to the post-war chaos, the connection to Berlin and Babelsberg was completely interrupted - once again there was a threat of closure due to lack of money. Hoffmeister was initially able to pay for the operation and staff from his savings, then the Carl Zeiss Foundation from Jena stepped in. When the East German Academy of Sciences was founded in April 1946 from what was left of the Prussian academy , the Sonneberg observatory was given the status of “non-university research” in the Soviet occupation zone. However, with the establishment of the Federal Republic of Germany (May 23, 1949) and the GDR , cooperation with the West became almost impossible. A certain substitute for this was the record archive that remained in Sonneberg , which Brandt helped to maintain and which, with tens of thousands of records, had been the second largest in the world since 1945.

Large telescopes and GDR politics

The erection of a 6 m dome (1946) and the employment of four young astronomers was a new challenge for the trained optician Brandt. A lens telescope with a focal length of 2 meters was accommodated in the dome , and a second new building was built in 1950: a laboratory house (project interplanetary matter by NB Richter ) with a 4.5 m dome attached. In 1951 a reflector telescope for photoelectric brightness measurements was set up in it, which served for over two decades.

Brandt was also involved in the largest installation to fill the Russian reparation gaps: the Schmidt camera 70/172 cm, set up in 1952 , on which Wolfgang Wenzel in particular worked. Instruments from the private observatory of Duke Ernst von Sachsen-Altenburg, which was dissolved in 1946, had to be adapted beforehand . The cooperation with master mechanic Reinhardt Lehmann , from whom u. a. a laboratory spectrograph is from (1955).

In 1957 and 1958 a new main observatory building with an 8-meter dome was finally erected and the installation of a large Schmidt camera, astrograph and (1958) the new 60 cm Cassegrain reflector telescope was organized. These experiences put Brandt - who continued to work as a hobby astronomer - in a position, as a book author, to deal with popular science , which is now more strongly funded in the East .

In the years up to 1962, the Sonneberg observation technology was enormously expanded both quantitatively and qualitatively: two new 40 cm astrographs (1960 from VEB Zeiss-Jena and 1961 from Hoffmeister's funds), as well as the one designed by Paul Ahnert and Hans Huth and built in the workshop Camera system for sky surveillance (1962). Now the entire northern sky and half of the southern sky (down to the declination of −35 °) can even be photographed in two light areas - yellow / green (photo-visual) and blue - within one night . This system is the most effective in the history of astronomy. It brought u. a. through Gerold A. Richter a breakthrough for the exploration of variable types and their galactic cosmogony. At the same time, the problems with the SED state leadership increased (removal of Hoffmeister in 1967, planned closure of the observatory in 1969, its integration into the new " Institute for Star Physics "). The general resistance to moving to Potsdam led to an absurd two-year ban on observing the large Sonneberg instruments - but this was secretly ignored. The longest photographic observation series in the world was not interrupted - also by Brandt's commitment.

In 1968 all GDR astronomers were forced to leave the Astronomical Society and all professional contact with the Federal Republic of Germany was severely restricted. Brandt and his colleagues nevertheless managed to stay up to date with astrophysical measurement technology .

With the political reunification of Germany on October 3, 1990, the Academy of Sciences of the GDR also ended as the sponsor of the observatory, which initially came under the care of the state of Brandenburg . In 1991/92 the evaluation commission recommended the closure, but it became a branch of the Thuringian state observatory in Tautenburg and in 1995 was given a private company to support it. Rudolf Brandt did not live to see the latest developments - he died in 1975, so that he was spared the last-mentioned disappointments for "his" Thuringian observatory.

Works (selection)

• Heavenly wonder in binoculars . Verlag Johann Ambrosius Barth, Leipzig 1938, 3rd edition 1952, 6th edition approx. 1970.

In addition the VdS : One of the most beautiful books ... 7 editions. Anyone who can get hold of such a copy [in the second-hand bookshop] should definitely grab it.

• The sky year . Astronomical Yearbook (3 co-authors). Kosmos-Verlag 1941–1948
• Ahnert's calendar for astronomers . Astronomical Yearbook (3 co-authors) JA Barth-Verlag Leipzig, from 1949
• The telescope of the star friend. Franckh-Kosmos, Stuttgart 1957/58 (further editions 1962 etc.)
• From the history of the Sonneberg observatory . Communications from the Sonneberg Observatory, special volume 57 (approx. 1965)
• Observing the sky with binoculars. Verlag Johann Ambrosius Barth Leipzig, 1972 (6 earlier editions under the title Himmelswunder im Feldstecher ).
• Sky observation with binoculars. An introduction for star lovers by Rudolf Brandt, Bernd Müller and Eberhard Splittgerber, Verlag Deutsch (Harri), 2006 and (bound) 2007.

Web links

• Binoculars for sky observation (Astronomie.de)
• Publications by R. Brandt in the Astrophysics Data System