The Lippert Astrograph

The Lippert Astrograph is named after its donor, Eduard Lippert, a prosperous merchant and amateur astronomer.

An astrograph is a light-sensitive refracting telescope used for astrophotography. Originally, three astrographs were arranged in parallel, allowing simultaneous observation with different colour filters.

The building was completed in 1909; however, the instrumental equipment could only be finalised in 1914. Subsequently, the instruments were subject to several modifications. In 1957, a reflector with approximately the same focal length replaced the large astrograph. The other two astrographs were removed. The new reflector was again modified in 1974. Only the middle segments remained on the mounting, equipped with counterweights. Of the original instruments, only a guiding scope and a finder scope have been preserved.

The Lippert Astrograph helped discover several comets and numerous minor planets.

Fig. 1: The Lippert Astrograph in its original configuration with three astrographs and additional guiding scopes and finder scopes.

Fig. 2: The Lippert telescope at the present

 

Comets

The nucleus of a comet resembles a dirty snowball: it is a mixture of ice and dust with a diameter of 1-10 kilometres. If the comet gets close enough to the Sun, some of its ice evaporates and forms an envelope of steam, methane, ammonia and other molecules – the so-called coma. Solar radiation and solar winds split the molecules into atoms and ions, which form the two tails. The solar wind sweeps away the ions of the coma, forming the plasma tail.

The solar radiation pressure squeezes out the dust particles released because of evaporation, forming the dust tail.

When passing close to the Sun or to Jupiter, a comet can be torn apart due to tidal forces. An excellent example is comet Shoemaker-Levy 9: When passing by Jupiter, it broke apart into a chain of 20 pieces. During its next rotation in 1994, the pieces fell into Jupiter one after another.

 

Fig. 3: Head (coma + nucleus) and tail of the comet Kohoutek discovered by the eponymous Hamburg astronomer in 1973,  Picture: 1974