Cartier Rotonde Terre et Lune (Earth and Moon)

Released this year at the Salon International Haute Horlogerie (SIHH) is a watch that places Cartier firmly in the league of the elite watchmakers in the world. The Rotonde de Cartier Terre et Lune, translated in English to Rotonde Earth and Moon, is a watch with a splendid astronomical complication where it shows the phases of the moon on demand.

The dial is made with from Lapis Lazuli, a stunning blue, which does the concept of the timepiece justice. The unique moon phase function works on demand by using the pushpiece at 4 o’clock on the case. Once pushed, a disk slides over the tourbillon aperture at 6 creating the moon phase. The tourbillon aperture represents the moon, while the lapis lazuli disk represents the shadow cast on it. There are few words that can describe just how incredible it is to see both of these complications – a tourbillon and an on demand moon phase in a single watch.

There is an Earth design on the subdial which displays the hours and minutes. This made from brushed 18kt white gold and rests on the blue lapis lazuli dial. On the outer ring of the subdial is a ring of Arabic numerals making up a GMT function. This ring rotates and the hour is indicated by a black triangle at the 12 position. This feature can be adjusted by the second pusher at the 2 position.

For a watch of this pedigree, it is implicit that it be made from platinum. To add to the watch’s exclusivity, Cartier has chosen to make only 50 examples of this stellar model. This timepiece comes in a case diameter of 47mm and it carries a blue cabochon sapphire set into the textured main crown. The case back uses an exhibition sapphire crystal for the viewing of the mechanical hand wound movement.

The movement used is the 9440 MC caliber with a 72 hour power reserve. The movement is decorated with star motif bridges connecting the 362 components that comprise the movement. The balance wheel on this model oscillates at 21,600 VpH.