Moon phase display

Moon phase display

It takes the moon 29 days, 12 hours, 44 minutes and 2.9 seconds to orbit the earth. The classic moon phase mechanism is rounded to 29.5 days. However, setting a mechanical gear train to half days is not the simplest of tasks. This is why the simpler version of the moon phase display uses a gear train with 59 teeth for two sets of 29.5 days. In the 50000-calibre family, first unveiled in 2015, larger moon phase wheels with a higher number of teeth reduce the deviation so drastically that a future inheritor of the watch would theoretically need to take it to a watchmaker to have the moon phase display adjusted by only 1 day in 577.5 years.