The movement used in Caliber 89 for the indication of Easter Day was patented in 1983 by three creators: Jean-Pierre Musy, François Devaud and Frédérique Zesiger. The patent application was filed by Patek Philippe.
For 150th anniversary in 1989 Patek Philippe constructed one of the most complex Caliber 89 watches. In addition to functions such as a split-seconds chronograph, moon phase, full perpetual calendar, equation of time, times of sunrise and sunset, grande and petite sonnerie; a minute repeater which chimes on four gongs and many others, it was equipped with one of the most unusual and difficult to perform indications: the date of Easter.
Notifier: Tomasz Jakubas
Other records: Timeline of Watchmaking Innovations