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sterrenkoepelThe department of Astronomy at Radboud University Nijmegen has two optical telescopes and a radio interferometer. The optical telescopes are installed in two domes on the southern wing of the Huygens building, and the radio dishes on the northern wing.

Optical telescopes

On the roof of the Faculty of Sciences, there are two domes hosting two telescopes: a historical refractor and a modern catadioptric.

The refractor is 20 cm in diameter and has a focal distance of 208 cm (f/ 10.4). The objective lens is a Littrow doublet, composed of an equiconvex crown glass lens and a second flint glass lens. It is mounted in a commercial equatorial mount Micron GM4000, that can be operated from the manual control and the computer. Also mounted in the same platform there are a finder (a 6cm-diameter refractor with a focal length of 70 cm, f/11.6, giving a field of view of 130 arcmin with current eyepiece) and an astrograph (14cm-diameter and focal length 70 cm, f/5).


It is a very special, priceless telescope. The tube and the focusing device, as well as the finder, were built in 1905 by Maurice Manent, and the main lens was built and tested by Dr. André Couder in 1932. It is older than the Waalbrug, the arch bridge over the Waal river inaugurated in 1936, that has become one of the identity signs of the city of Nijmegen. Over a hundred years old, everything is in perfect condition and fully operational. We use the telescope for solar projection observations, public observations and astrophotography.

The catadioptric telescope is a 14-inch (35.6 cm) diameter Schmidt-Cassegrain with 3.56-m focal distance (f/10), a Meade LX200GPS model. It includes a finder with 53mm-diameter and 8x magnification. It is also mounted in a commercial equatorial mount Micron GM4000, that can be operated from the manual control and the computer. We have a few eyepieces that provide fields of view in the range 12-33 arcmin. We also have a CCD camera with a wheel of filters, model SBIG-ST-10XME, and a 2184×1472 pix (3.2 Mpix) detector covering a ~15×10 arcmin field of view. We use this telescope to teach students how to work with CCD cameras, and for a few science projects. In the summer of 2016, an auto-guiding camera and a motor focuser were installed improving the capabilities of the telescope for scientific observations.

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A detailed description on how to operate the 14-inch catadioptric telescope can be found here. If you want to learn how to use the telescope mount with the computer click here. If you are an experienced observer and you have received the specific training to operate the telescopes, you can book nights for the two telescopes:

For information about upcoming training sessions to learn how to to operate these telescopes, please click here.

Radio telescopes

The Astrophysics Department owns its own radio telescope, a 2-element radio interferometer, which is located on the roof of the Huygens building. This makes the Radboud University the only university in the Netherlands with their own radio interferometer. The Radio Interferometer (RIF) consists of two 3.5-m dishes and is used for teaching and student projects. It was completely refurbished in 2011/2012, where both the mechanics and the electronics of the Radio Interferometer have been completely renewed. The RIF was re-opened on 29 June 2012, and it was renamed the Ulrich J. Schwarz Radio Interferometer.


The Netherlands has always been at the forefront of radio astronomy. This started first with the 25-meter Dwingeloo Telescope in the fifties and sixties, then the Westerbork Synthesis Radio Telescope consisting of 14 x 25-meter telescope dishes since the seventies, and now the Low Frequency Array LOFAR. The RIF contributes to training of the next generation Dutch and Dutch-educated radio astronomers and as such helps to maintain the leading Dutch position in worldwide radio astronomy.

Ulrich J. Schwarz

Ulrich Schwarz is a pioneer of radio astronomy, who moved from his native Switzerland to the Netherlands to be involved in the first generation of radio telescopes. These included the Dwingeloo telescope and the Westerbork Synthesis Radio Telescope array. He also pioneered interferometry at the Parkes radio telescope in Australia. Through the effort of early pioneers such as Ulrich Schwarz, the Netherlands is today among the most pre-eminent countries in radio astronomy in the world.

After his retirement and move to Arnhem, Ulrich became the guardian of the Radio Interferometer at the Radboud University Nijmegen. He supervised the use of the Radio Interferometer within the physics student curriculum. During the move to the new Huygens-building he provided the inspiration and overview for the complete refurbishm ent of the Radio Interferometer.

For an overview of Ulrich's life and career, please find the presentation given by Hugo van Woerden during the renaming of the radio interferometer here.

User Manual

A copy of the user manual can be found here.