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Review: Rotonde de Cartier Astromystérieux Watch

It may be completely transparent in its construct, but the Rotonde de Cartier Astromystérieux remains shrouded in – what else but – mystery.

Oct 28, 2016 | By Celine Yap

Isn’t there a saying about doing something for a very long time, that you become really good at it? Well, Cartier has been producing mystery clocks for more than a century, and true enough, its latest creation proved to be its most impressive one yet, not least in terms of mechanics.

The history of Cartier’s mystery clocks go back to the early 20th century when Louis Cartier met an exceptional clockmaker named Maurice Couet who specialized in mysterious clocks. Couet had been inspired by the works of French clockmaker-turned-illusionist, Jean-Eugène Robert-Houdin. With Cartier, he successfully began production of these clocks with hands not directly linked to the movement, but attached to two crystal discs (one for the hours hand and another for the minutes) fitted with serrated metal edges. The first mystery clock made was named Model A and it left Couet’s workshop in 1912.

In 2014, Cartier revisited the mystery clock concept. The R&D team, headed by Carole Forestier, found a way to miniaturise the movement to make it suitable for a wristwatch. Rotonde de Cartier Mysterious Hours was the opening salvo that paved the way for other modern-era mysterious timepieces, including the Rotonde de Cartier Mysterious Double Tourbillon. The latter was especially memorable because the mystery wasn’t in the way it told the time, but rather, how its flying tourbillon rotated with no apparent connection to the movement. Completing one full rotation in 60 seconds, the tourbillon provides a powerful burst of visual dynamics never before seen in other mystery timepieces.Cartier Rotonde de Cartier Astromysterieux

Following in the footsteps of the Mysterious Double Tourbillon, the Astromystérieux also used the rotating toothed sapphire discs concept for purposes other than to tell the time, namely, theatrics. And who would complain about that? As a matter of fact, knowing Forestier and her penchant for orbital complications, the realisation of a watch like the Astromystérieux was just a matter of time.

The mystery clock typically shows only the hours and minutes, keeping everything else away from sight. Indeed, that’s the whole point of a mystery clock – to display the time without any apparent connection with the movement. Astromystérieux, however, puts the entire movement on display, in addition to the hands. So then where’s the mystery? Take a closer look and you will begin to wonder how the movement, which is apparently suspended in midair, gets any power. How does one wind up the mainspring in this watch, when there are no mechanics connecting the barrel and the crown?

This astonishing movement, Calibre 9462 MC, utilises a completely novel concept where the escapement, balance wheel, gear train, and barrel are all held together by a set of plates and bridges. This collective unit effectively functions as the minute indicator because it completes one full turn every hour; the minutes hand is affixed to the movement thusly. Because of this rotation about a central axis, the entire construct is practically a flying tourbillon, although not in the most conventional sense.

A system of four sapphire discs holds the secret to the Astromystérieux. In lieu of a traditional carriage, the entire movement revolves, not just the balance and escapement, as its lower bridge is one of the four sapphire discs. Two upper bridges (one for the balance wheel and another for the escapement, gear train, and barrel) complete the construct that forms the tourbillon carriage. The hours are indicated by way of a second sapphire disc, which is linked to the tourbillon lower disc.Cartier Rotonde de Cartier Astromysterieux

Solving the mystery of how the Astromystérieux gets its power is a disc-based winding system that brings the third sapphire disc into play. This patented system connects the barrel with the crown using a floating pinion between the winding shaft and winding disc, allowing the movement to be wound only when the crown is in the correct position. A disconnectable system has also been developed so that the crown’s winding shaft and the barrel cannot be broken in the event of excessive winding.

Finally, the fourth sapphire disc is used to set the time. Situated at the base of the movement, it provides the motion required to turn the tourbillon carriage, but when the crown is pulled, it engages the time-setting system. All this is made possible because of a revolutionary lever that blocks the sapphire disc during the normal running of the watch. When the crown is pulled, it frees the lower sapphire disc, thus also freeing the tourbillon carriage (linked to the minutes wheel) and allowing time to be adjusted.

Although the negative space around the movement communicates a feeling of simplicity and emptiness, the Astromystérieux is anything but. This juxtaposition between the complex and the pure is perhaps the single most alluring thing about this awe-inspiring watch.


  • Dimensions: 43.5mm
  • Functions: Hours, minutes
  • Power Reserve: 50 hours
  • Movement: Manual-winding Calibre 9462 MC with mysterious central tourbillon
  • Material: Palladium
  • Water Resistance: 30 meters
  • Strap: Black alligator leather with double adjustable folding clasp

This story was first published in World of Watches.

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