The Oskar Luehning Telescope

Constructed in 1975, with a 1.2m diameter mirror, the Oskar Luehning Telescope is the largest and the newest telescope at Hamburg Observatory. Still, the dome and the mounting date back to 1954. Initially, this building hosted the Great Hamburg Schmidtspiegel that was later shipped to Spain.

A donation from the Nikolaus Luehning foundation financed the telescope in 1974. It is named after the son of Nikolaus, Oskar Luehning, who intended to study Astronomy, but died in World War II before he could.

Since 2001, the telescope has been equipped with a modern CCD camera, which has a field-of-view of a quarter of the diameter of the Moon. The computer-aided control of the dome and the telescope enables remote observations via the internet.

Besides the telescope, the building hosts a vaporisation plant for cleaning and coating mirrors.

 

Fig. 1: The Oskar Luehning telescope

Fig. 2: The Schmidt-Spiegel at Calar Alto/Spain

 

 

Sky surveys

After World War II, photographic sky surveys with the Schmidt telescopes designed in Bergedorf became an important research area. The Great Schmidt-Spiegel was inaugurated in 1954. However, since the observing conditions in Bergedorf were inadequate from the very beginning, the instrument was transferred to Calar Alto in the South of Spain in the early 1970s.

The Schmidt-Spiegel reached its prime with the “Hamburg Quasar Survey” (HQS) performed in Spain from 1985 to 1997. A prism installed on the objective lens allows extraction of high-resolution spectra from the stellar images. The shape of these spectra helps scientists differentiate between the objects observed. With this method, numerous quasars and interesting stars and galaxies were discovered.

Today, the era of photography in astronomy is over. Like the Oskar Luehning Telescope, the Hamburg Schmidt Spiegel on the Calar Alto was equipped with a CCD camera in 2015 and has been used remotely to observe asteroids and comets since.

 Figures: Section from photoplates with quasar spectrum. The indicated object in the figures is quasar HS 1700+6416, discovered at Hamburg Observatory. The other objects are stars.