Khan Academy: Emmoser, Celestial Globe With Clockwork

In this video [2:56] Met curator Clare Vincent on art and science in Gerhard Emmoser's Celestial globe with clockwork, 1579. The movement rotated in the celestial sphere and drove a small image of the sun along the path of the ecliptic. The hour was indicated on a dial mounted at the top of the globe's axis and the day of the year appeared on a calendar rotating in the instrument's horizon ring.