
With the new Rotonde de Cartier Astroregulateur (ref. W1556211) limited edition, Cartier has found yet another, maybe even more effective, way of combating the problem of gravity affecting the accuracy of mechanical movements. The solution is as simple as it is ingenious.
As you probably already know, the accuracy of a mechanical movement is constantly affected by chaotic motions of its owner’s hand and the gravity pull of Earth.
Around 216 years ago the Swiss watchmaking genius Abraham-Louis Breguet confronted the problem with his “tourbillon” system by putting the escapement and the balance into a rotating carriage that, theoretically, would have somewhat balanced out the negative effects of the force of attraction.
However, while truly spectacular and even mesmerizing, the tourbillon failed to significantly increase the accuracy of a mechanical movement and some time ago Cartier decided to attack the problem from another flank: by putting the escapement on to the oscillating weight to ensure that it will always stay upright.
To make the system work, Cartier’s engineers invested five years of their lives and applied for four patents describing a system that comprises “two differentials that change the speed transmitted by the wrist to the micro-rotor into a constant speed, thus ensuring the regular advance of the seconds indicator that moves with the rotor and, therefore, the good timing performance of the” [Astroregulateur].

Called Calibre 9800 MC, the new movement is not only technically sophisticated but is also really, immensely huge.
While the diameter of the hulk is more or less average at 35.80 mm, the thickness of the caliber is somewhat staggering at impressive 10.10 millimeters. This is quite a height for a micro-rotor type of movement that usually shaves a millimeter or two off the usual thickness of an automatic caliber with a “full-size” oscillating weight.
As you can see on the “explosion” render above, the mechanism consists of three plates (with the front one that houses the bulk of the moving parts as thick that it can easily be called a ‘ring’) stacked against each other to achieve maximum structural rigidity and thus — accuracy.
No wonder that the gadget is presented in a case that measures a whole 18 millimeters from top to bottom. I don’t know whether the team behind the ref. W1556211 tried to make the final product look more proportional or simply wanted to piggyback on the current “supersize me” trend among ultra-luxury timekeepers, but the gadget’s Niobium-Titanium case comes in a larger-than-life size of whole 50 millimeters!
To make the final product easier on a wrist, Cartier crafted the case in ultra-light niobium-titanium alloy that is often used in superconducting magnets. As a result, the weight of the chunky case was reduced to only 55 grams. The French jeweler plans to produce the Rotonde de Cartier Astroregulateur in a limited series of 50 individually numbered pieces. Together, they will probably cost like the International Space Station*.
See also: Pasha de Cartier Skeleton Flying Tourbillon in White Gold
WWR Verdict
Originality 5/5
Build Quality: 5/5
Usability: 4/5
Overall Legibility: 3.5/5
Nighttime Legibility: 1/5
Value for Money: 4/5
Overall Rating: 4.5/5
* UPDATE ON PRICE: In the USA, the W1556211 will cost $270,000. But you probably know how it works: if you have to ask…
Photos: Cartier
Cartier Rotonde de Cartier Astroregulateur (ref. W1556211) specification
Price: $270,000 (MSRP)
Movement: Cartier Caliber 9800 MC, micro-rotor, 281 components, 35.80 mm in diameter, 10.10 mm in height, in-house, Swiss Made
Winding: Automatic
Jewels: 43
Cadence of balance: 21,600 vph
Movement decoration: Cotes de Geneve stripes, circular-grained mainplate
Functions: Hours, minutes, seconds
Power reserve: 80 hours
Case: Niobium-titanium
Shape: Round
Size: 50.00 mm
Case height: 18.00 mm
Dial: Galvanic guilloche, silvered openwork grill with sunburst effect
Numerals: Roman, black, transferred
Hands: Blued steel, sword-shaped
Hour markers: Black dots (on the minute track)
Water resistance: 30 meters
Strap: Black alligator skin with double adjustable folding clasp in 18-karat white gold
Crystal: Sapphire, antireflective
Back: Sapphire