For a technological upgrade of his observatory at Hohentübingen Castle, Johann Gottlieb Friedrich Bohnenberger (1765–1831) – the inventor of the gyroscope – ordered one of the most modern angle measuring devices of his time, a large circle of repetition, from the company Reichenbach & Utzschneider in Munich. Especially for this instrument, which was delivered in 1814, Bohnenberger had built the small observatory on the eastern bulwark of the castle with a rotating dome. This ensemble of the original instrument along with the first ground observatory that was specially built for this purpose at the zero position of the land survey thus represents a historical singularity.