After launching the most complicated pocket watch ever made in 2015, Swiss watchmaker Vacheron Constantin is at it again. Well, in this case, they have been at it for the past five years, which is the amount of time it took to develop their most complicated wristwatch ever – the Les Cabinotiers Celestia Astronomical Grand Complication 3600 – that debuted today at SIHH.

Incredibly, the renowned Swiss manufacture was able to fit 23 functions inside a 36 mm x 8.7 mm movement, ultimately resulting in a case measuring just 45 mm x 13.6 mm. And best of all, thanks to the unique twin-dial configuration, where the front and back both act as dials, the legibility of all the distinctive functions is quite good.

Furthermore, to put it in context, caliber 3600 has 514 total components, 64 jewels, 6 power barrels, and a power reserve of 3 weeks (21 days/504 hours).

As described by Vacheron Constantin, “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.”

The complete list of functions are hours, minutes, perpetual calendar, day/night indication, precision moon phase, age of the moon, running equation of time, sunrise and sunset time, day and night length, seasons, solstices, equinoxes and zodiacal signs, tide level indicator, Sun-Earth-Moon conjunction, opposition and quadrature, transparent sky chart of the northern hemisphere with indication of the Milky Way, of the ecliptic and celestial equator, hours and minutes of sidereal time, tourbillon, 3 weeks of power reserve (6 barrels), and power reserve indication.

The Vacheron Constantin Les Cabinotiers Celestia Astronomical Grand Complication 3600 (Ref. 9720C/000G-B281) is regulated by a tourbillon escapement that runs at 2.5Hz (18,000 vph) and comes in an 18K white gold case that is water-resistant to 30 meters. This is a unique piece (one-of-a-kind).