Behind its favorable legibility and apparent simplicity, the Astrocalendaire is equipped with a complex system that serves both the protection and the ease of use of the calendar mechanism. What Cartier refers to as a “partially patented gear train mechanism”, essentially is a replacement to most levers and springs that are used in the majority of perpetual calendar’s mechanisms. The importance of this new system is to be found in the fragility of the more traditional solutions, where one risked severely damaging the calendar by over-winding the movement or trying to change the date “at inadvisable times” – usually a few hours before and after midnight when the mechanism is at work.

As in the case of just about all highly and uniquely complicated Cartier movements, the Astrocalendaire had also been developed by Carole Forestier-Kasapi, the Head of Fine Watchmaking at the brand. Beyond creating the multi-tier display and the protective gear train mechanism for this caliber, she and her team also designed a new setting-mechanism that should make adjusting the calendar’s displays easier compared to most perpetual calendar watches. The majority of such watches have a number of tiny pushers set into the side of the case, with which the day, month and other indications can be set.

In the case of the Astrocalendaire, the wearer can set the time, the date and the month through the crown, and do so in both “directions”, forwards and backwards. While not completely unique to this watch – or manufacture -, it is a difficult task to achieve such ease of use with a mechanism as complex and fragile as the perpetual calendar. The difficulties involved are further proven by the fact that even in the case of this in-house developed caliber, all but one of the calendar’s functions are set using the crown. The day is still adjusted by a small pusher set in the side of the case.

Finally, creating a more balanced look for the dial, the hours and minutes sub dial and the “amphitheater of dates” blend nicely into a discreet 8-symbol, further strengthening the wimpled trend of the use of “8” – a number and figure with special importance to loyal (and important) customers from the Far East. This subtle twist in the dial’s layout although certainly brings some balance to it, should make reading the time more difficult between four and eight o’clock. But you can always spend that time just gazing at the flying tourbillon. Housed in a 47 mm wide platinum case the Astrocalendaire is a limited edition of only 100 pieces and is priced at €150,000 or around $205,000. cartier.com