Astronomy in Lilienthal

Lilienthal Observatory

After the reconstruction of the 27-foot reflector telescope from 1793

An experience for young and old

In order to bring the significant astronomy history of Lilienthals closer to children, teenagers, and adults, and to inspire them to support the reconstruction of the Lilienthal Observatory, the AVL Astronomical Association Lilienthal e.V. was founded in 2000. The association’s statutes include a commitment to preserve the historical legacy of Johann Hieronymus Schroeter the Lilienthal chief administrator and astronomer, as well as to aim for the reconstruction of the largest instrument at the observatory, the 27-foot reflector telescope from 1793.

Book your Visit
Tour for Schools

The Creation of the TELESCOPIUM-Lilienthal Observatory

After several years of intensive planning, which was repeatedly revised under the working title TELESCOPIUM-Lilienthal, the original project  —initially envisioned as a science center, the construction of historical observation stations, and a planetarium—has now become a reality with the reconstruktion of the 27-foot telescope.

27-foot reflector telescope with visitor information. Photo: K.-D. Uhden

At the entrance to Lilienthal, opposite the Borgfelder Landhaus, a faithful replica of Schroeter’s Newtonian reflector telescope was built, according to the technical description provided by Schroeter. The telescope features a mirror diameter of 50 cm and a focal length of 8 meters.

The so-called mount, which is used to align the telescope with the observed object, is a fork-like wooden structure resting on a masonry tower that stands about 7 meters tall. The device, with its tube, the observer’s platform, and the visitors on it, can be rotated horizontally around the central axis of the tower.

The diameter of the outer tracking circle is 22 meters. The height adjustment of the tube with the optics is done via a pulley system.

To compensate for the Earth’s rotation, the telescope is manually moved by the observer using gear and spindle drives. The side view into the tube via the eyepiece is located at the upper end of the tube, on a platform that offers space for several people. Access to the platform is possible via a staircase inside the tower or a separate external ladder structure.

End of the tube with refractor and azimuth drive. Photo: H.-J. Leue

The instrument has been adapted to modern construction and safety standards, while the historically documented handling has been largely preserved.

The goal is to demonstrate how and with what technology astronomical observations were made more than 200 years ago, and what results and insights the astronomers of that time were able to achieve.

Due to the light pollution from Lilienthal and Bremen, the focus will primarily be on observing objects within the solar system, namely the Sun, the Moon, and the planets.

In calm air, the lunar craters with their many facets during the changing phases of the Moon, the cloud belts on Jupiter with the motion of its four large moons, the ring system of the planet Saturn, or the structures on the Sun’s surface can be seen with great brilliance.

Observing through a historical large telescope will leave a lasting impression on the visitor.

H. J. Leue (translated)