The Antikythera mechanism

The Antikythera mechanism was originally housed in a wooden box about the size of a shoebox with dials on the outside and a complex clockwork assembly of gears inscribed and configured to produce solar and lunar positions in synchronization with the calendar year. By rotating a handle on its side, its owner could read on its front and back dials the progressions of the lunar and synodic months over four-year cycles. The device has been estimated to be accurate to 1 part in 40,000.

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