Vacheron Constantin Artelier Cabinotiers Celestia Astronomical Grand Complication 3600 Ref. 9720C/000G-B281

The twin-dial Celestia Astronomical Grand Complication 3600 from Vacheron Constantin's Artelier Cabinotiers was introduced at SIHH 2017. It combines astronomy and the watchmaking art in a white gold case of 45mm. Twenty-three essentially astronomical complications appear on the front and back dials of the watch, providing a reading of time in three modes – civil, solar and sidereal – each driven by its own gear train. Embodying the height of technical sophistication, its new fully integrated 514-part caliber measures a mere 8.7 mm thick, while six barrels guarantee three full weeks of power reserve. It is said to have taken five years of development.