Back in the 18th century on the top floors or under the roofs of Geneva's buildings, horologers set their ateliers, called cabinets, in order to receive the most of natural light for executing their craft. Dubbed cabinotiers, they were inspired by astronomy, mechanical engineering and the arts in making exceptional timepieces.
Today, Vacheron Constantin's Les Cabinotiers department combines artistic crafts with watchmaking expertise to create grand complications and unique pieces.
A marriage of astronomy and mythology, Les Cabinotiers Grande Complication Bacchus is a new one-of-a-kind masterpiece which boasts 16 complications.
Vacheron Constantin is the oldest watchmaker in continuous operation since it was founded in 1755. Astronomical watches have long been a part of the heritage, with the first perpetual calendar integrated into a double-sided yellow gold pocket watch documented in its archives in 1884.
The Le Temps Céleste theme had the Les Cabinotiers department revisiting the astronomical origins of time measurement, and creating the double-sided Les Cabinotiers Grande Complication Bacchus boasting calendar and astronomical functions.
On the upper part of the dial, the perpetual calendar shows the date, day and month on three counters as well as the leap-year cycle in a small aperture within the minute repeater's torque indicator. The complication tracks the Gregorian calendar's vagaries without any need for adjustment until 2100.
The complex mechanics of this piece also provide an astronomical reading of time representing a tribute to Johannes Kepler (1571-1630), regarded as one of the founders of modern astronomy for having discovered the laws of planetary motion.
The astronomical functions include the equation of time positioned between 10 and 11 o'clock.
The Earth's path around the Sun is not circular but elliptical, and the Earth's axis is inclined at 24 degrees to the plane of its orbit. Hence the time between two zenith passages of the Sun is not the same throughout the year.
This difference between the true solar day and the average 24-hour civil day ranges from -16 to +14 minutes depending on the time of year, and coincides only four times a year.
Called the equation of time, or time correction in astronomical language, this differential is displayed by a dedicated pointer, while sunrise and sunset times -- adjusted according to a reference city -- appear at the bottom of the dial.
Another astronomical system on the back side of the watch, the sidereal time indication comprises a rotating disc depicting the celestial vault with its constellations observable from the Northern Hemisphere.
Taking a fixed star in the sky as a reference point, the time required for the Earth to complete a full 360-degree rotation, or sidereal day, is exactly 23 hours, 56 minutes and 4 seconds.
On the Bacchus, the celestial disc thus performs a complete rotation according to sidereal time with the time displayed on the periphery.
The date is read off by a large central hand moving over the fixed outer flange bearing a scale graduated in five-day increments. This hand also indicates the sign of the zodiac, the season and the four dates corresponding to the solstices and equinoxes.
Finally, the small central hand indicates the age of the Moon, ie, the number of days that have elapsed since the last Full Moon.
Other complications include a tourbillon regulator to compensate for the effects of the Earth's gravity on the mechanism, and a minute repeater chiming the hours, quarters and minutes on demand.
To avoid unnecessary noise as well as wear and tear on the mechanism, the striking of the gongs is equipped with a centripetal flying strike regulator. This perfectly silent device regulates the duration of the musical sequences so as to obtain clear, distinct and regular sounds.
In addition, the 47mm pink gold case has been specifically designed to provide the best possible sound quality for the minute repeater.
The beauty of the case is exalted by Les Cabinotier's master engraver and gemsettter, who worked more than 300 hours on the exquisite decoration composed of vine leaves interspersed with bunches of ruby grapes.
In tribute to Bacchus, the decoration continues on the bezel and caseback with a hand engraving depicting vine leaves.
Through the Les Cabinotiers Grande Complication Bacchus, Vacheron Constantin perpetuates the grand tradition of crafting both richly decorated and mechanically complex timepieces while setting astronomical functions in a starring role.
