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Wendelstein Observatory

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University Observatory Munich
Faculty of Physics of the Ludwig-Maximilians-Universität

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2-m telescope
40-cm telescope
20-cm coronograph
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80-cm telescope 1989–2008
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Deutsche Fassung

Wendelstein in winter
Universitäts-Sternwarte München / Observatorium Wendelstein
Scheinerstr. 1, D-81679 München, Deutschland
Telefon +49-89-2180-6001 · Telefax +49-89-2180-6003 · Internet: name@usm.uni-muenchen.de

Wendelsteingipfel, D-83735 Bayrischzell, Deutschland
Telefon +49-8023-8198-0 · Telefax +49-8023-8198-29 · Internet: name@usm.uni-muenchen.de




The Wendelstein Observatory

Site description

The Wendelstein Observatory is situated on the summit of Mount Wendelstein, a prominent, 1838 m high mountain in the bavarian Alps. It is operated by the University Observatory of the University of Munich.

Wendelstein in summer
Wendelstein Observatory in 2001

Geographical coordinates:   WENDELSTEIN OBSERVATORY
University Observatory Munich
D-83735 Bayrischzell
Telephone +49 8023 8198 0
Fax +49 8023 8198 29
Latitude: 47° 42′ 13.1″ North
Longitude: 12° 00′ 43.4″ East

Only 75 km south-east of Munich, after one hour's drive this site can easily be reached via cable car (8 min) or by means of a cog rail road (25 min.). Final access (personal only) to the very top is achieved by an elevator climbing up 109 m within the mountain. The observatory was first installed to survey the solar activity. In the mid-1980, it was redirected to night observations of stars and galaxies, but it still owns a 20 cm Zeiss solar coronograph. Nowadays, the coronograph is used only for eduction and public outreach. For the night time activity, a 80 cm DFM-telescope was installed which was operated until spring 2008 for scientific observing programs every clear night. It was equipped with high-tech focal instruments like high-speed multichannel photometers or a direct imaging CCD-Camera. This instrumentation has often been involved in international observing programs. In 2007, a 40 cm telescope was installed for the students lab.
The main scientific facility is a 2 m Fraunhofer telescope installed in 2011 which replace the 80 cm telecope and is installed at the old site of the 80 cm telescope. The telescope will be finally equipped with four instruments, an optical wide field imager, a theree channel (optical to NIR) imager, a high resolution echelle spectrograph, and a field spectrograph for kinematical studies. The cameras are operational at the telescope, the echelle spectrograph will be installed in summer 2016.





Meteorological Conditions:

The weather conditions at Wendelstein are highly seasonal with sometimes more than 1m of snow in winter time and decent warmth in summer. But cold weather may occur at any time of the year.


Above the clouds at sunset

Above the clouds at sunset

Compared to other sites in Germany the meteorological conditions at Wendelstein have turned out to be fairly good. During typical years about 120 nights with less than 2/8 cloud cover can be used for astronomical observations. Extremely dark nights often occur in autumn when the upper cloud layers may reach altitudes of 1500 - 1800 m thus preventing light pollution by some nearby small villages. Seeing conditions have been studied in April through December 1998 using a copy of the ESO Paranal Seeing Monitor kindly made available by ESO (e.g., ESO La Silla and Paranal in Chile, Calar Alto in Spain).




Telescope and Instrumentation:

2.0m Fraunhofer Telescope

Since September 2011, the new telescope is installed at the observatory. It saw first light on Dec 19, 2011. Regular use of the telescope started Nov 13, 2013. The telecope was build by Kayser-Threde GmbH (München) and Astelco System GmbH (Martinsried). It is installed in a 8.5 m diameter dome build by Baader Planetarium (Mammendorf) The three large mirrors of the telecope were produced by Lytkarino Opical Glass Factory (LZOS, Moskau).

The telescope is of the Ritchey-Chrétien type with a free aperture of 2.0 meter and focal ratio of f/7.8. The light is redirected through a tunable and plane third mirror it one of the two Nasmyth-focal stations. At both stations, instruments with up to 350 kg and a field-of-view up to 0.7 degree can be installed (right now, only one station has a 3-lens corrector system). One station is equipped with an already operational wide field imager CCD camera. The other station will house an optical-NIR CCD camera (smaller f.o.v.) and the fiber connections to two spectrographs, installed outside the dome in the observatory building. Telescope operation can be done locally or by remote control.

The scientific instruments are all developed and build by the Universitätssternwarte München:

Wendelstein 2-m telescope

Wendelstein 2 m Fraunhofer Telescope built by Kayser-Threde (München) and Astelco (Martinsried), shown with its wide field CCD camera.

The wide field camera (WWFI) allows images up to an size of 0.5 degree (full moon diameter). Right now, first science programs have started while a major focus is still the testing of all telescope modes. The camera is based on a mosaic of 4 CCDs \ (each 4048 × 4048 pixels) from the company e2v, which have been put into a computer controlled detector system by Spectral Instruments (Tucson). Up to 14 filters can be installed (so far u', g', r', i'), and a so-called Bonn shutter is in use in front of the detectors.

Spiral galaxy NGC 891

Image of the spiral galaxy NGC 891 (Andromeda), taken with the Wendelstein 2 m Fraunhofer teleskoce and its WWFI camera. The images was put together from individual exposures in filters u′, g′, and r′ the combination corresponds to the impression of the human eye. NGC 891 is similar to our own Milky Way host galaxy, but seen edge-on. It has a distance of about 30 million light years.

A three channel camera (two optical CCDs and one infrare Hawaii2R detecotor system) are still under final construction. An echelle spectrograph for high resolution spectra is under tests in the Munich labs while the field spectrograph VIRUSW for medium resolution is on loan at the 2.7m telescope of the McDonald Observatory (Texas) producing already scientific data.

The new telescope will be a corner stone for the observational science projects of the Universitäts-Sternwarte München, especially for the projects within the Clusters of the German Exzellenzinitiative “Origin and Structure of the Universe”. Further, the Munich programs using our parts of the observing time of 9m Hobby-Eberly Telescope in Texas will be supported through coordinated observations. More information about telescope and instruments can be found in a couple of publications.

Galaxy M33 Perseus galaxy cluster Galaxies M65 and M66
Towards the end of the years 2013, 2014 and 2015, the archive of the WWFI images was screened for nice-looking observations which allowed to produce so-called true-color images. 2013, we selected our neighbor spiral galaxy M33 (left). 2014, a deep image of the Perseus galaxy cluster was produced (middle). In 2015, the Galaxies M65 and M66, members of a nearby small group of galaxies, were the targets. Technically, the procedure was the same as described above for NGC 891. Here, all three images cover about 0.5 degree along the side (about the diameter of the full moon), that's the size of one camera field of view.

40 cm Teleskop

A 40 cm Cassegrain telecope purchased from ASTELCO was installed in 2007 in the old 3m dome. The telescope is equipped with an ST-10 CCD camera. The filter wheel contains SDSS g', r' and i' as well as Johnson B and V filters. The f/8 systems yields a pixel scale of 0.44''/CCD pixel. A fiber link connects to a small low-to-medium resolution Cassegrain spectrograph originally build for the old 80 cm telescope by DFM. It is only used for the students lab.

The telescope is be used for the student lab, for Nova monitoring towards M31, and extinction monitoring. It thus supports the 2 m class telescope. The 40-years-old aluminium dome crashed during the commissionig of the 40 cm telescope and was replaced by a new 3.2m Baader dome.

Old dome of the Wendelstein 40-cm telescope New dome of the Wendelstein 40-cm telescope Globular cluster M15
Wendelstein 40 cm telescope New 3.2 m dome 7.5 min R band image of the globular cluster M15 (18/12/2007).

20 cm Coronograph

A special 20 cm refracor, built by Zeiss-Oberkochen, was used until 1988 to observe the activity of the sun in white light, Halpha, and by spectra. The telescope allows to place special light stops (the so-called coronographic design which produces artificial solar eclipses) allowing to observe the solar atmosphere under excellent atmospheric conditions. The telescope is used for public outreach and student eduction.

Solar activity data taken at Wendelstein have been digitzed for the years 1947 und 1982 and are available from the Solar Data Services of the National Geophysical Data Center (Boulder).

Solar prominences Wendelstein solar telescope Hα image of the sun
20 cm Coronograph (middle) and historic photographic records of active solar protuberance.
Large solar spot group Small solar spot at the limb Prominences and spot at the solar limb
CCD (Basler UK-1151) exposures with a Baader-H-alpha filter at the 20 cm coronograph. Left: Big sun spot group as observed 27.10.2014. Middle: Small sun spot as observed near the solar rim 11.6.2014. Left: Protuberances and solar spot 22.6.2014.



Observing Programs


  • 2m-WWFI
    • coma structure of comet 67P
    • transits of exo-planets
    • variable sources including gravitaional lensing events in the Andromeda- and Triangulum galaxies (M31, M33)
    • strukture of the brightest galaxies in clusters of galaxies
    • weak lensing studies of cluster of galaxies detected by the Planck sattelite
  • 40cm-ST10 und PSPEC
    • extinktion monitor
    • Delta-Cep stars of the Milky Way
    • variable red giant monitoring in galactic globular clusters
    • students’ lab
  • Observational and instrumental lab at Wendelstein:

In all modes of observations, students have the chance to participate and get trained in modern observing and instrument development. Up to now, a total of 59 diploma/master/bachelor theses and PhD works has been done at the observatory since 1989 (until start of 2014). Furthermore, a large number of publications has been based on data collected partly or totally at the observatory. The participation in international campaigns has been requested quite often supporting parallel observing with sattelite telescopes or world wide nets of ground based facilities. Guest observers from USA, Sweden, Argentina, and China have made use of the telescope.




Staff:

Prof. Ralf Bender responsible full professor
Dr. Ulrich Hopp director
Dr. Claus Gössl Wide field imager, instrument control and station software
Dr. Frank Grupp Optical designs, high-resolution spectrograph FOCES
Dipl.-Phys. Florian Lang Mechanics, 3KK three channel (optical-NIR) imager
Dipl.-Geophys. Wolfgang Mitsch Technical director
Christoph Ries service observer, night assistent
Dr. A. Riffeser public outreach, observing programs, data reduction software
Michael Schmidt service observer, night assistent

Last updated June 2016 by A. Riffeser (arri@usm.lmu.de)