What is a moon phase watch?

Watchmakers have long mastered the art of adding complications to their watches. One of the most fascinating and elegant of these complications is the moon phase.

A dial that changes with the moon

A moon phase watch is characterized by its dial that automatically reproduces the phases of the lunar cycle. Thanks to this complication, the watch displays the full moon, the new moon, the first and last quarter of the moon. On a moon phase watch, the moon begins its course on the left side of the dial. This is the beginning of the lunar month and the first phase of the cycle during which the moon is waxing. In the middle of the month, the moon is full and is displayed on the watch as a solid circle. The waning phase then begins until the moon disappears completely to the right of the dial, before reappearing again to the left, for a new cycle.

A history of more than a century

The moon phase watch was invented in 1925 by the Swiss watch company Patek Philippe. This first moon phase watch was called the Perpetual Calendar 97975. This elegant wristwatch was also the first to feature a true perpetual calendar. However, another moon phase object existed before this watch. It was a women’s pendant made by the same company in 1898, 27 years before the watch.

Since then, this innovation by Patek Philippe has inspired countless watchmakers and today there are many models of moon phase watches on the market. Among them, the Rolex Ref. 6062 from 1953, the Patek Philippe Grandmaster Chime Ref. 5175, the watchmaker’s most complicated watch, or the Jaeger-Lecoultre Duomètre Sphérotourbillon Moon. These watches, in addition to their great beauty, achieve, for the most part, the feat of remaining accurate for thousands of hours.

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