Politechnic Institute, Vienna – Georg Merz, Munich 1858.
Focal distance: 164 cm
Aperture: 116 mm

The instrument, equipped with optics from the Munich Optician Georg Merz, was located at the top of the tower, in a specially built rotating dome. It was used primarily for observations of comets and asteroids, but from 1870 onwards it was also used for solar physics studies: in fact, the Hofmann direct vision spectroscope was adapted to it, thus becoming the main research tool in the field of astrophysical studies.