The model shows the no longer existing observatory, which was in a tower of the southern Göttingen city wall, in today’s tower road. It was only a few steps away from his apartment in (today) Langen Geismarstraße 49. Inside the observatory, the typical instruments that Tobias Mayer had at his disposal are shown: telescopes and protractors. In a gap in the right part of the building is a large quadrant, with which Mayer has measured the entire starry sky. He compiled a star catalog with 998 accurately measured fixed stars. A similar quadrant as a replica of the Mayer device in Göttingen is set up at the Marbach train station. Mayer had the device specially made by John Bird in London and transported to Göttingen.
Together with J.A. von Segner, in 1751 he took over the management of the university observatory, which was still under construction. The work at the university and the construction of the observatory give him barely time to continue his employent with the moon movement. In February 1756, the great wall Quadrant (Radius 6 feet) of Bird from England arrived and was installed; Mayer can continue his observations in optimal conditions in the now most modern equipped observatory.