Cartier's idea was to invent a creative central display that stems from a revolutionary concept. Designed like an amphitheatre, with the intention of clarifying the perpetual calendar's indications, the Rotonde de Cartier Astrocalendaire's display is a true watchmaking feat. It overcomes numerous readability issues that are specific to the traditional approach to this complication, which requires the juxtaposition of twelve months, seven days, the date and the type of year in a diameter of just a few centimetres.
Arranged three-dimensionally in concentric levels, the display of the perpetual calendar's functions is spread over the different levels: the day is indicated on the first. It is followed by the month on the second, which is itself surmounted by the date. Thin windows move along these tiers. The perpetual calendar's final function is indicated by a hand located on the back of watch and shows what type of year it is: a leap year or a common year.
Consisting of gear trains, the construction of the Rotonde de Cartier Astrocalendaire watch's movement is a watchmaking exploit that solves all the functional and ergonomic problems connected with this type of complication. It breaks away from the design of traditional perpetual calendars and introduces an alternative that enables any risk of breakage to be anticipated, adjustment errors to be resolved and chronometry to be improved.
Partially patented, the gear train system of the Rotonde de Cartier Astrocalendaire's 9459 MC movement replaces the traditional lever and spring mechanisms with a gear train mechanism that substantially limits the risk of breakage when the watch is over-wound at inadvisable times. The traditional design of a perpetual calendar prohibits any manual correction several hours before and after midnight at the risk of breaking the mechanism. The adjustments made using four minuscule push-pieces on the side of the case are impractical and never clearly identified.
This problem no longer exists with the Rotonde de Cartier Astrocalendaire watch's movement thanks to a setting system that uses the crown. In addition to the traditional setting of the hour and minute, the crown also controls the date and month indicators.
This ease of use is further increased by the possibility of correcting the functions both forwards and backwards.
The Rotonde de Cartier Astrocalendaire watch houses at its heart a flying tourbillon: a complication that is emblematic of the Fine Watchmaking collection.
The Rotonde de Cartier Astrocalendaire watch is certified "Poinçon de Genève". The self-winding calibre 9459 MC is assembled and adjusted in the new Cartier Fine Watchmaking workshops located in the heart of Geneva, upstairs from the Cartier boutique on the rue de Rhône. Its finishings were carried out according to the standards of the most prestigious watchmaking certification.