Small armillary sphere, 17th century.
© Science Museum / Science & Society Picture Library
This European bras armillary sphere was made in the 17th century, but has been mounted on a later 19th century base with horizon ring. The decorative stand, probably French, consists of a figure of the ancient Greek figure of Atlas standing on an ebonised wooden plinth. The armillary sphere is a demonstration device to explain the movements of the Sun, Moon, stars and planets acros the sky. Its interlocking rings can be used to teach astronomical principles in the same manner as a celestial globe, or it can act as a model of the universe. Based on the premise of an Earth-centred universe, the armillary sphere had to be modified in the 17th century in order to teach the new theory that the Earth orbits the Sun.