In modern watchmaking, a perpetual calendar indicates the date, and corrects automatically for months with less than 31 days, as well as leap years. Unless the movement takes into account century years that are not leap years, a watch with a perpetual calendar will need manual adjusting in 2100, 2200 and 2300 but not in 2400. Usually, a perpetual calendar combines additional complications (a moon-phase, for example). From WatchTime’s February 2018 issue (on sale now), here are six watches that are (almost) ready for eternity. PATEK PHILIPPE PERPETUAL CALENDAR REF. 5940
Patek Philippe Perpetual Calendar Ref. 5940
Patek Philippe’s cushion-shaped Perpetual Calendar Ref. 5940 is now also available with a rose-gold case. It is powered by Patek?s ultra-thin Caliber 240 Q with micro-rotor. The case measures 37 mm by 44.6 mm. The Ref. 5940R-001 is available for $87,320.
 
HERME?S SLIM D’HERME?S QUANTIE?ME PERPE?TUEL
...