The Front Dial of the Antikythera Mechanism

Abstract

The Antikythera Mechanism, found in a shipwreck dating from the first century B.C., is the oldest geared mechanism known. Its general function was astronomical or calendrical, but the exact nature of the display on its front dial remains uncertain. We know that the places in the Zodiac of the Sun and Moon were shown, and the date. The author has previously argued that the places of the five planets known in antiquity must also have been shown. He devised mechanism to drive these indications, and demonstrated the viability of his reconstruction by building a working model. Reviewing his earlier publications, he clarifies obscure points and shows how recent study by others supports his arrangement of the display. Others, again, have proposed an interesting alternative to some parts of his restored mechanism for the planetary indications. It bears a close relationship to the device found in the original instrument for modelling the lunar anomaly, and may offer certain practical advantages. The author welcomes the new proposal, and suggests its further development. He concludes, however, that as yet there is no compelling reason to abandon any significant part of the reconstruction that he previously proposed.