Cartier, famed for its so-called “mystery clocks,” lately has been transferring that technology to wristwatches. The Rotonde de Cartier Astromystérieux, introduced at this year’s SIHH, is Cartier’s third “mystery” wristwatch, after the Mysterious Hour and Mysterious Double Tourbillon. In this one, central hour and minutes hands appear to be floating in a 25.7-mm space in the center of the watch, while rotating around the dial. Floating with them are the escapement, balance wheel, gear train and barrel, arranged along a central axis.
The revolving escapement makes the Astromystérieux a very unconventional tourbillon. Cartier calls it “a groundbreaking and ingenious new interpretation of the tourbillon.” The “mysterious” part of the watch consists of four stacked sapphire disks, all made in-house: an hour disk, a tourbillon disk, a winding disk and a fixed disk. In conventional tourbillons, the escapement and balance wheel are in a cage, which rotates to counteract the effects of gravity on the movement. Here the rotating disks replace the cage. A sapphire disk with a large diameter serves as the lower bridge, together with two upper bridges, one holding the balance wheel and the other the escapement, gear train, and barrel. The watch uses the same principle as Cartier mystery clocks do: in a mystery clock, the hands are not linked directly to the movement but to the disks. The disks are fitted with serrated metal edges and are turned by the movement. In the case of clocks, the movement is hidden at the base of the clock; in watches, the movement’s components are assembled around the four disks at the edge of the dial. The hour disk is linked to the tourbillon disk, which completes one rotation per hour.
The new hand-wound movement (Caliber 9462 MC) is made in-house and consists of 408 parts, including 188 ball bearings. It has a power reserve of about 50 hours. Cartier has registered patents for the movement’s winding system, time-setting system and brake lever system.
The Cartier Rotonde de Cartier Astromystérieux watch has a palladium case that is 43.5 mm. in diameter and 12 mm thick. The watch is a limited edition of 100 pieces. It costs $181,000.