Greubel Forsey may have just broken their own mould with their first sports luxe watch (emphasis on the luxe), but now they’re returning to something they know intimately: the perpetual calendar or, in their own terminology, the Quantieme Perpetual (QP), this time with Equation of Time thrown in for good measure.
Equation of time, for those not well-versed in astrological complications, calculates the discrepancy between mean solar time – the theoretical position of the sun, if it’s movement in the sky were to remain constant – and apparent solar time, where it actually appears to be. Essentially, it’s the difference between a sundial and a clock.
It’s about as useful a complication as a moon phase as nobody needs to know true solar time; we just consider the changes seasonal and keep to a standard 24-hour day. But it is an impressive feat nonetheless, and on the QP à Équation it’s the key reason to flip the watch over and take a look at the caseback. You just read off the number where the blue or red line (denoting – or + minutes) intersects the white scale. Letters indicate months; colours indicate seasons and the semi-circles indicate equinoxes.
Beneath it you can see what Greubel Forsey dub their ‘mechanical computer’, the patented mechanical labyrinth of cams and shifting fingers that calculates both the QP and equation of time features.
The Equation of Time is sat alongside the year indicator, meaning the two pieces of info you don’t really need are hidden away on the back. The rest of the calendar – day, date and month – are all readable at a second dial-side, in-line with one another. The leap year indicator is just next to it at 6 o’clock, meaning that despite the huge number of indications it’s a phenomenally east-to-read take on the perpetual calendar.
It’s joined by central running hours and minutes, with seconds sequestered on a subdial at 7.30, cut off slightly by Greubel Forsey’s signature, 25 degree inclined 24-second tourbillon, and a 24-hour day-night indicator just below it.
The final flourish is the power reserve indicator at 2.30, vital for a watch that you never really want to see power down. Even with the bidirectional crown making things easier, setting a perpetual calendar is inevitable a pain.
All of the above is surrounded by an understandably substantial 43.5mm rose gold case, but given everything that it fits inside isn’t too large at all. It’s the same size in fact as the standard QP, despite the complicated addition. Paired with a chocolate brown dial, it’s one of the loveliest-looking Greubel Forsey’s to date. Here’s hoping we get to see it in the glamorous flesh soon.
Price & Specs:
Model Name: Greubel Forsey QP à Équation
Case/Dial: 43.5mm diameter x 16mm thickness, 5N red gold
Water resistance: 30m
Functions: Hours and minutes, small seconds, 24-second tourbillon, 24-hour, power reserve, perpetual calendar with a disc-based display, mode selector display, equation of time and year displays on caseback
Frequency: 21,600 vph (3 Hz)
Power reserve: 72h
Strap: Brown alligator leather with red gold folding clasp
Price: CHF 670,000 Swiss Francs
More details at Greubel Forsey’s website.