SIHH 2014: Greubel Forsey QP à Équation Written byWatchTimeJanuary 22, 2014 The perpetual calendar timepieces on our wrists today are not only among the oldest horological complications, they are descended from devices used by the clergy during the Middle Ages to calculate seasonal feasts. For 2014, Greubel Forsey will create a unique perpetual calendar combined with an Equation of Time, all in an easy to read and easy to use, though not necessarily easy to afford timepiece called the QP à Équation. The brand’s priority was to simplify the complete displays and make it easier to set the perpetual calendar. The latter is achieved by means of a bi-directional winding crown that makes this complicated watch as easy to set as a standard date-only watch. If your timepiece has stopped for several days and you need to set it quickly, simply pull out the crown, checking the selection indicator near 2 o’clock. Turn the crown back and forth, and all the indications change. If you go too far, you just go back through the days until you get to the right date. It’s easy. As you might expect, some sophisticated complexity underlies this simplicity, and three patents have been filed on the movement. A stack of cams with movable fingers shift the indications on the front and back dials of the timepiece, the complete mechanism fitting entirely within the movement. The cam for the months changes the month in a window on the front display and also moves the Equation of Time scale on the back. The years’ cam controls the leap year indication on the front, and that of the seasons on the back. Reading the primary displays requires just a glance at the subdial at 3 o’clock. There, three in-line windows indicate the day, the date and the month. The large date makes the calendar even easier to read. The Equation of Time indication is found on the back of the watch, along with the seasons and the current year in four figures. The indications on the back are made up of two superimposed transparent discs in synthetic sapphire crystal. The first disc is driven by the date wheel and has a scale in minutes indicating the difference between solar and mean time. The second disc, which goes around once a year, has a figure shaped like a manta ray, and divided into four sections in red and blue to show whether the Equation of Time is positive or negative. To find out, look where the red line (positive difference) or the blue line (negative difference) crosses the scale. This Equation of Time display is unprecedented and provides a clearer appreciation of the Earth’s elliptical orbit around the sun as well as the equinoxes and solstices. The QP à ÉQUATION in white gold measures 43.5mm in diameter and is 16mm high. It includes a fourth patent the 24-second Tourbillon inclined at 25°. The balance oscillates at 21,600v/h and the power reserve is 72 hours from two fast-rotation superimposed barrels that feature protection against excess tension. This leaves space for a large free-sprung balance. The movement diameter is 37mm (16.41 lignes), height 9.55mm and comprises 570 components and 65 jewels. Greubel Forsey will produce five examples of the QP à Équation for 2014, each priced at SFr.670,000.