Technology and instruments

With our large telescope, the »Bamberg refractor«, you can observe objects in the sky when the weather is clear. What we can show varies depending on the time of day and the observability of the celestial bodies. When the sky is overcast, an object in the city is shown to illustrate the magnification capabilities of the telescope. Unfortunately, the dome of the observatory cannot be opened when it rains or snows, so then we concentrate more on the technical aspect of observing the sky.

Bamberg Refractor

The main instrument of the Wilhelm-Foerster-Sternwarte is the so-called Bamberg Refractor, a 12-inch refractor with a focal length of five metres. It was built in 1889 by the Carl Bamberg company in Berlin-Friedenau for the newly founded Urania. With its mount, the telescope weighs 4.5 tons, but can still be easily moved with one hand. During the public guided tours in the 11-metre-high dome of the observatory, magnifications of 70x to 700x are used as required.

6-inch double refractor

The smallest dome of the Wilhelm-Foerster-Sternwarte, with a diameter of five metres, houses a 6-inch double refractor (lens diameter approx. 15.25 cm). This telescope with a focal length of 2.25 metres is used exclusively for amateur observations. One striking feature is the lens in one of the telescopes, which has an excellent imaging quality and sharpness with a 3-lens ZEISS-B lens. The second telescope of the double refractor is equipped with a 15 cm lens from Wolfgang Busch with a focal length of 2.3 metres. Next to it, another refractor telescope is mounted: a 12 cm refractor with a focal length of 1.82 metres for solar observation in the light of the H-alpha hydrogen line, equipped with a Halle-Lyot filter.

ZEISS RC reflector telescope

In the 7m dome of the observatory is a ZEISS RC reflector telescope with an aperture of 75 cm. The focal length is 5.6 metres, the drives are computer controlled. The reflecting telescope with its excellent imaging quality was used for guided tours as well as for amateur observations, especially for astrophotography. At present, the instrument is not in operation, as a comprehensive overhaul is necessary.