The movement is Vacheron’s caliber 2755, which in addition to showing the time also includes a minute repeater, a tourbillon, and a perpetual calendar. In addition, there are a number of astronomical indications, including the Equation of Time, sunrise and sunset times, a sky chart with sidereal hours and minutes (sidereal time, you’ll recall, is based on a day defined by the transit of a star rather than of the Sun) the age and phase of the Moon, the signs of the zodiac, and the seasons.