Baselworld 2010: Patek Philippe Ref. 5159R Perpetual Calendar

Baselworld 2010. Patek Philippe has released our favorite perpetual calendar watch, the Ref. 5159, in rose gold.

What is a perpetual calendar? Many watches display the date, and even the month on their dial. But since some months have only thirty, twenty-nine of twenty-eight days, you need to adjust the date at least five time per year. A perpetual calendar is a mechanism that automatically takes into account the varying number of days in each month as well as leap years so that the watch displays the correct date each month without the need of adjustment.

Patek Philippe Ref. 5159R. The Patek Philippe Ref. 5159R is one of the company's grand complication watches. It is a perpetual calendar watch with the retrograde complication.


The Patek Philippe Ref. 5159R is a revision of the Ref. 5059, with the case diameter of 38 millimeters. Powering the Ref. 5159 is Patek's caliber 315 S QR movement. The self winding movement produces 28,800 vibrations per hour, resulting in a smooth sweeping seconds hand. The movement has a 44 hour power reserve. The movement automatically recognizes the duration of each month and keeps track of leap years.

The dial of the watch displays the day and month in apertures at the 9 and 3 o'clock positions. The date is displayed by a red-tipped fourth hand, which runs from the 8 o'clock to the 4 o'clock position. This hand moves clockwise from the 8 o'clock to the 4 o'clock position, along a 270 degree arc, slowly over the period of one month, and than jumps back to the number 1 at the end of the month moving in the reverse direction. This is the retrograde motion.

The month setting, tells the watch whether it should send the hand back to 1 after the 28th, 30th or 31st day. A small aperture just below the 12 o'clock displays the Roman numerals I, II, III or IV. This is the leap year indicator. When it displays a I, II or III, the watch will send the date hand back to one after the 28th day of the month of February. When it reads IV, the watch will send the date hand back to one after the 29th day of the month of February. The month setting and the leap year setting allows the watch to adjust the movement of the date hand accordingly, this creating a perpetual calendar mechanism.

The Ref. 5159R also has of the moon-phase mechanism which remains accurate for 122 years and 45 days, and then only has to be corrected by one day.


A sapphire-crystal case back reveals the intricate self-winding mechanism and the 21K gold rotor. A dust cover protects the sapphire crystal case back.

Other than the new Rose Gold model, the Ref. 5159 is also available in 18K yellow (Ref. 5159J) or white gold (Ref. 5159G) .

About Patek Philippe. Patek Philippe & Co. was founded in Switzerland in 1851. The companies emblem, the Calatrava Cross, was adopted by it at the end of the 19th Century. It is acknowledged as one of the finest, if not the finest, watchmaker in the world.