Philipp Immser (alias Ymbser, 16th century)
Astronomical clock, Strasburg, 1555-1557
Vienna, Technisches Museum für Industrie und Gewerbe, inv. 11939

This spectacular astronomical clock is a compendium of the Ptolemaic conception of the universe. It illustrates the zodiac and indicates the irregular motions of the planets and the Sun, the phases of the Moon, the duration of the day and the night, the current time, the day of the week and so on. The celestial sphere performs a complete rotation every 24 hours.