Bloomberg Anywhere Remote Login Bloomberg Terminal Demo Request


Connecting decision makers to a dynamic network of information, people and ideas, Bloomberg quickly and accurately delivers business and financial information, news and insight around the world.


Financial Products

Enterprise Products


Customer Support

  • Americas

    +1 212 318 2000

  • Europe, Middle East, & Africa

    +44 20 7330 7500

  • Asia Pacific

    +65 6212 1000


Industry Products

Media Services

Follow Us

Bloomberg Customers

Inside the Wristwatch, as You've Never Seen It Before

By Mark Bernardo - 2014-03-18T04:00:06Z

Photograph by Tom Schierlitz

Company Symbol % Change
3 of 8

Moon Phase

This complication, which arose from astronomical clocks popular in the 19th century, found its way into wristwatches in the 20th. The traditional moon-phase mechanism consists of a disk with two identical, illustrated moons. A 59-notch gear, controlled by a mechanical finger, drives the disk, advancing it one notch every 24 hours. Thus, the disk makes a complete revolution every 59 days, or roughly two lunar cycles, with the appropriate moon phase revealed through an aperture. (The so-called astronomical moon phase has a gear that’s even more in sync with the true lunar cycle of 29.53 days.) Blancpain helped revive interest in the moon phase in 1983, and the company continues to lead with models such as the Quantième Complet 8 Jours.