One of the last hints before the full unveiling on Sept 17.
What will be the world's most complicated watch features a surprising and unique complication: the indication of the Metonic cycle
Named after Meton, a 5th-century BC Athenian astronomer, the period of the Metonic cycle is 19 years and is notable because it is an almost perfect multiple between a solar year and a lunar month.
19 years is almost exactly equal to 235 lunar months and totals 6,940 full days. The difference between the two periods of 19 years and 235 synodic months is only a few hours. The Metonic cycle can be also be used to predict eclipses and is used for the calculation of the date of Easter every year.
Considering a year to be 1⁄19 of this 6,940-day cycle gives a year length of 365 + 1⁄4 + 1⁄76 days which is slightly more than 12 lunar months. To keep a 12-month lunar year in pace with the solar year, an extra 13th month is added on seven occasions during the nineteen-year period.
The in-house watchmaking team at Vacheron Constantin have developed the Metonic cycle indication as an integral part of a new and special calendar, one of three interrelated but entirely different calendar systems incorporated within this watch.