Trend-spotting in the watch business is low impact sport. Watches just don’t follow the same pace as fashion. The lead times are too long, two years and up for even simple movement changes, and the form is too restrictive. Quality watches are meant to be looked after for the next generation. Nevertheless, tendencies do emerge, as this year’s SIHH revealed, where five of the 19 luxury watch brands unveiled watches with astronomical themes.
Equation of Time, which shows the difference between calendar time and actual time based on solar observation, and associated complications are not unknown – Breguet’s Marie-Antoinette watch included this function – but are still much rarer than tourbillions or minute repeaters – due in no small part to the fact they are almost more difficult to explain than make.
The tourbillon is both highly complicated and ambitious. However, for those prepared to put time into choosing a watch, Equation of Time is curiously rewarding both for its almost quixotic lack of a contemporary application (they’re useful for setting up sundials) and for the historical importance of astronomical time-keeping.
Panerai, a company not known for complicated watches, enters the field with one of the smartest astronomical version, in celebration of the 400th anniversary of Galileo Galilei’s first observation of the moons of Jupiter, which ultimately led to acceptance that the earth rotates around the sun. Panerai is celebrating Galileo’s work, which also includes experiments on the isochronism of pendulums, with their Luminor 1950 Equation of Time Tourbillon Titanio. The most technically sophisticated wristwatch ever made by Panerai, it comprises a 30-second tourbillon that rotates perpendicular to the axis of the balance (as with their first tourbillon), the equation of time, sunrise and sunset times, and a sky chart on the case-back, these last functions being set to the owner’s choice of location.
As you might expect, knowledge of the Equation of Time was crucial to both the development of astronomy and as part of the solution to the longitude problem. A corresponding variation in sidereal (ie astronomical) time is dealt with by Jaeger-LeCoultre’s Jaeger Grande Tradition Grande Complication, which pairs a minute-repeater with a flying tourbillon and a sidereal zodiac calendar. The flying tourbillon acts as the hour hand but is calibrated to the 23 hours, 56 minutes and 4 seconds (4.091 strictly) of the sidereal day, and in case the astronomic emphasis is not clear enough, there is a zodiac calendar on the outside of the dial.
Audemars Piguet and Vacheron Constantin have created more traditional Equation of Time watches, treating the idea as a refinement of the perpetual calendar idea. Audemars’ Royal Oak has an existing movement seen for the first time in the Royal Oak case, while Vacheron’s watch, the Patrimony Traditionnelle, incorporates a tourbillon, as well as the perpetual calendar and equation of time functions. It is also notable for a 14-day power reserve.
Cartier's Rotonde de Cartier, as a trotourbillon watch it houses Calibre 9451 MC, a mechanical movement with manual winding. This beautiful timepiece from Cartier's fine watchmaking collection offers a power reserve of approx. 48 hours. Water-resistant to 30 metros, this watch has a 47-mm diameter.
But perhaps the most interesting and surprising offer was from Girard-Perregaux, who showed a 1966 with a stripped down Equation of Time, which will cost around £25,000 – a fraction of the price commanded by the more complicated watches. The Girard-Perregaux 1966 Annual Calendar and Equation of Time contains the GP033M0 automatic movement and it offers a minimum of 46 hours of power reserve. Impressive functions include house, minute and small second display, along with an annual calendar and the equation of time
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