Munich’s eye on the sky
Munich’s first eye on the sky was the Observatory which opened in Bogenhausen in 1816. The Observatory was incorporated into LMU in 1937/38. This year the University Observatory Munich celebrates its bicentenary.
It’s a 10-minute bike ride from LMU’s Main Building in the Maxvorstadt to the Scheinerstrasse in Bogenhausen. When the University’s Observatory was set up in 1816, the bicycle as we know it had not yet been invented. It wasn’t until the following year that Karl Drais introduced his velocipede (Laufmaschine), the first incarnation of the front-and-back two-wheeler principle. The Observatory’s first Director, Johann Georg von Soldner (1776–1833), made the trip from the city to his workplace on horseback. The horse came with the job, because in 1816 Bogenhausen was out in the country, far enough away from Munich to afford a panoramic view of the sky. It was therefore an ideal spot for an astronomical observatory. Needless to say, that is no longer the case, and the instruments that von Soldner had at his disposal have also been rendered obsolete by 200 years of progress. However, the original Observatory still stands, and it still houses one of the most advanced telescopes of its day. The refractor was designed by the famous physicist and optical instrument maker Joseph von Fraunhofer. Installed in 1835, it was technically the finest telescope in the world – if only for the short span of 4 years.
The University Observatory Munich (Universitäts-Sternwarte München, USM) is still one of the most renowned institutions of its kind in Germany, though its observational activities are no longer located in Bavarian capital. Its excellent reputation rests on the instrumental capabilities of the Wendelstein Observatory, which is perched on the peak of the same name in the Bavarian Alps and became part of LMU in 1949. In 2013, a state-of-the-art 2-m telescope officially went into operation there. “The telescope is ideal for teaching purposes, for follow-up observations of objects of moderate luminosity and for long-term observation programs,” says Professor Ralf Bender, the Observatory’s present Director.
But the USM has more to offer than a modern optical telescope. It also builds instruments for use with telescopes elsewhere, including the European Southern Observatory (ESO) in Chile. Only recently, astrophysicists and engineers at the USM teamed up with colleagues in Germany and England to construct an instrument destined for use at ESO: KMOS has now been installed on one of ESO’s 8-m telescopes in Chile. KMOS stands for ‘K-Band Multi-Object Spectrograph, and as the name implies, it can provide spatially resolved infrared spectra for up to 24 objects simultaneously. Meanwhile, its builders’ attentions have turned to an even more spectacular project, the construction of the ‘first-light’ camera for what will be the largest telescope in the world, ESO’s 39-m European Extremely Large Telescope (E-ELT), which will also be erected in Chile and is scheduled to go into operation in 2024. The USM is also a partner in the 10-m Hobby-Ebberly Telescope in Texas. “International research collaborations are tremendously important for us,” says Bender.
The first stellar spectra
Bender’s early predecessors, such as Soldner and Johann von Lamont (1805-1879, who was originally from Scotland), had their priorities too. During his time at the Observatory, Soldner worked out the theoretical basis for the Bavarian Ordnance Survey. But, of course, he didn’t just survey terrestrial landmarks. In 1814, Fraunhofer had discovered the multitude of dark lines in the solar spectrum. During Soldner’s tenure in Bogenhausen, the Observatory’s telescopes recorded the first spectra of stars, thus initiating the field of stellar spectroscopy, which would enable astronomers to determine the composition of the elements in a star’s atmosphere. Lamont, on the other hand, focused primarily on the field of geophysics, and in particular on terrestrial magnetism. Indeed, thanks to Lamont‘s measurement campaigns, Bogenhausen became Europe’s first Magnetic Observatory. This tradition is still alive today, at LMU’s Geophysical Observatory in Fürstenfeldbruck.
“The era of Soldner, Fraunhofer and Lamont represents the first highlight in the Observatory’s history,” Professor Bender says. Hugo von Seeliger (1849-1924) was the first Director to focus on the more theoretical aspects of astronomy. Seeliger was not very interested in classical observational astronomy, i.e., cataloguing the properties of individual stars. His goal was to understand the large-scale distribution of stars in space, with the help of mathematical methods. His most famous graduate student was Karl Schwarzschild, who as Director of the Potsdam Observatory would make several ground-breaking contributions to astrophysics and the theory of relativity.
The decades following Seeliger’s tenure, marked by the rise and fall of the Third Reich, were a period of stagnation. The construction of a new building for the Institute of Astronomy under the leadership of Peter Wellmann in the 1960s and the reorientation of its research work towards modern stellar astrophysics, led by Rolf-Peter Kudritzki in the 1980s, form the basis for the present Observatory’s success. With the arrival of Ralf Bender, the range of the research done at the Observatory was extended to include extragalactic astronomy and cosmology. And the increased emphasis placed on the design and construction of instrumentation has meant that the USM now enjoys an enviable international reputation in this field. Having been incorporated into LMU’s Faculty of Physics in 1937, the USM now finds itself part of an outstandingly rich constellation of astrophysical institutions. In Garching, just beyond the city limits, lie the Max Planck Institutes for Astrophysics and for Extraterrestrial Physics, the headquarters of the European Southern Observatory (ESO) and the “Universe” Cluster of Excellence jointly hosted by TUM and LMU, of which the USM is an integral component. “We cover the whole portfolio here,” says Ralf Bender, “from astrophysics through planet formation and dynamics to cosmology.” Its close links with fundamental physics also explain why the decision has been taken to relocate the USM, together with the Faculty of Physics, in Schwabing. You don’t need a bike to get from Leopoldstrasse ro Schwabing. It’s just a leisurely stroll away.