Lifting the mystery of the Astromystérieux

Mysterious dials have been in the Cartier collection for over a century, but the latest wristwatch incarnation sets new standards in the genre.

Cartier’s high-end movement development director Carole Forrestier-Kasapi does not do things by halves. So before we even begin to describe the brand’s new Astromystérieux model we need to revisit what we know about the tourbillon. It was Mrs Forrestier-Kasapi who stressed the importance of looking at the “claims” of a patent when WorldTempus discussed the subject of the central tourbillon with her. As part of her job, she needs to be able to navigate the complicated verbiage of a patent with the same ease as you or I might read our daily newspaper. In Breguet’s original patent for the tourbillon, for example, there was no claim that the tourbillon cage should rotate in one minute, nor that the balance should be located at the centre of the tourbillon carriage.

Lifting the mystery of the Astromystérieux

These two elements are important for the Astromystérieux, since it has a tourbillon which performs one complete rotation in an hour, rather than a minute, and has its entire going train aligned longitudinally. The more horologically aware will already know that the key to the “mysterious” complication is the use of sapphire discs. But this usually takes the form of just two superimposed sapphire discs for the hours and minutes. In the case of the Cartier Astromystérieux, almost the entire movement assembly seems to be floating in mid air. So how, for example, do you wind the watch and set the time? There is a crown in the usual position at 3 o’clock, but for an extra touch of mystery there is no visible connection between the crown and the magical ballet being played out on the dial!

Here is where all the technical genius of Cartier comes into play: The mysterious display is governed by a total of four different sapphire discs. The bottom disc is fixed and rotates once per hour when engaged but when the crown is pulled out a floating pinion between the winding stem and the fixed disc frees up the latter to allow the time to be set. Three different patent applications have been filed just for this apparently simple operation: one for the winding system with a floating pivot, one for the time setting by sapphire disc and one for a brake lever system to prevent overwinding.

Lifting the mystery of the Astromystérieux

A second sapphire disc houses the hour hand, which is driven by a system of peripheral gears that converts the one-hour rotation of the tourbillon into a 12-hour rotation. The third disc is the true heart of the Astromystérieux, accommodating the barrel, gear train, escapement, balance and even the minute hand. Because the minute hand is attached directly to a movement bridge, the movement itself has to be utterly precise to ensure a precise indication of the minutes. A fourth disc seals the ensemble in a 25.7mm diameter aperture in a case that is 43mm in diameter, leaving just an 8.65mm band for the Roman numeral hour markers, underneath which the teeth, ball bearings and winding system to move the discs are hidden.

Just 100 Astromystérieux models will be available with a palladium Rotonde case for an appropriately astronomical price of 170,000 Swiss francs.

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