The Greubel Forsey Quantième Pérpétuel à Équation is an amazing piece of watchmaking. The perpetual calendar and equation of time is coordinated by a mechanical computer. We explained this in detail in our article On the GF Invention no. 7: the Compuetur Mechanic here. And now, the watch is improved with a new interpretation which Greubel Forsey calls the QP à Équation Millesimé Edition.
The Greubel Forsey QP à Équation Millesimé Edition comprises of 624 parts, three patents, and the combination of two inventions. The watch features one of the oldest watchmaking complications, the perpetual calendar, and incorporates an equation of time. But the Greubel Forsey has to be simple to use, regardless of being a complicated watch. All corrections, including for the days, can be rapidly made by turning the bi-directional crown.
description and all you need to know about how this movement works.
This new interpretation of the perpetual calendar features the Equation of Time incorporated within it, along with the addition of new functions and displays that aim to optimise readability and pleasure of use. Three apertures lined up in the sub-dial at 3 o’clock give an unequivocal indication of the day, date and month for enhanced visual comfort. The large date boosts readability, making it especially easy to make out the elements of the calendar.
The Mechanical Computer sits at the heart of the system. Greubel Forsey’s seventh invention, the computer is an integrated 25 part component with cams which are coded with the information needed for the functionality. These cams are stacked in a coaxial manner, with movable fingers to read the information. Depending on their rotation speeds and number of teeth, these wheels provide a variety of information. The Mechanical Computer also directly drives a system of sapphire disks that displays the equation of time, i.e. the difference between the “real” solar time and civil time.
The watch has two faces to display 15 indications . On the dial side, the QP à Équation indicates leap years, the 24 hours of the day and night, the day of the week, the large date, the month, the hours, the minutes and the seconds, as well as the chronometric 72-hour power reserve.
On the movement side, this timepiece displays the equation of time with the months, seasons, solstices and equinoxes, as well as the calendar year.
Also on the dial side is the Greubel Forsey signature of a tourbillon inclined at 25°, and with a fast 24 second rotation speed. This fast rotation and the inclined angle is designed to solve the critical positions of the oscillator in relation to gravity.
This new Millésime’s white gold case measures 43.5 mm by 16 mm thick and provides a simplified linear display. Herein lies the happy paradox of this piece: it is an ultra-complicated timepiece with its tourbillon and its complete equation of time perpetual calendar function, but it is as easy to use and adjust as a watch with three hands. This system is extremely easy to adjust in both directions without damaging the mechanism.
Retail price is CHF 670’000 before taxes.