Orrery (nonfiction)

An orrery made by Benjamin Martin in London in 1766, used by John Winthrop to teach astronomy at Harvard, on display at the Putnam Gallery in the Harvard Science Center.

An orrery is a mechanical model of the solar system that illustrates or predicts the relative positions and motions of the planets and moons, usually according to the heliocentric model.

It may also represent the relative sizes of these bodies; but since accurate scaling is often not practical due to the actual large ratio differences, a subdued approximation may be used instead.

Though the Greeks had working planetaria, the first orrery that was a planetarium of the modern era was produced in 1704, and one was presented to Charles Boyle, 4th Earl of Orrery – whence the name.

They are typically driven by a clockwork mechanism with a globe representing the Sun at the center, and with a planet at the end of each of the arms.

Nonfiction cross-reference

• David Rittenhouse (nonfiction)

External links:

• Orrery @ Wikipedia