Vacheron Constantin: Les Cabinotiers Celestia Astronomical Grand Complication 360026 January 2017
Vacheron Constantin presents Les Cabinotiers Celestia Astronomical Grand Complication 3600. Five years of development starting from a blank page, a dedicated master-watchmaker, along with two years of design, have given life to the one-of-a-kind Les Cabinotiers Celestia Astronomical Grand Complication 3600, displaying 23 complications on its twin dials. This Haute Horlogerie ‘heavenly phenomenon’ is one of the most complex ever made.
A remarkable feat of miniaturisation and engineering, the new Vacheron Constantin Caliber 3600 – an integrated movement comprising 514-part while measuring just 8.7 mm thick – controls more than 20 functions and has a three-week power reserve. It is yet another vivid demonstration of the technical expertise cultivated by the Maison in the field of astronomical complications.
Three Times: Civil, Solar and Sidereal
Its captivating functions notably feature the triple-time civil, solar and sidereal displays powered by three distinct gear trains, including a “tropical” gear train dedicated to all the solar functions.
Swept over by a pair of white gold open-tipped hands, civil (or standard) time is read off in the traditional manner on the front dial. Civil time is a universally recognised mean time based on the fictional principle that the Sun moves around the equator at a constant speed throughout the year, averaging one full turn every 24 hours. This convenient and conventional choice divides the year into 365.25 days, each day into 24 hours and each hour into 60 minutes.
True solar time is on the other hand based on the visible trajectory of the Sun in the course of the day, expressed through its hour angle measured at a given place and time. Depending on the day of the year, the difference between solar time and mean time ranges from +14 to -16 minutes, with the two exactly coinciding only four times a year. This discrepancy is due to the fact that the Earth’s orbit is elliptical (and not round); that the Sun is not in the centre of this ellipse; that the Earth does not follow this orbit at a constant speed; and lastly that the Earth’s rotation axis is tilted in relation to the plane of its orbit.
Thirdly, sidereal time is read off on the back of the watch. Technically regarded as an astronomical time scale based on the Earth’s rate of rotation measured with respect to the apparent motion of the ‘fixed’ stars as observed from a local meridian, sidereal time differs from mean time by approximately four minutes per day, meaning that 24 sidereal hours correspond to 23 hours, 56 minutes and 4 seconds of civil time. Sidereal hours and minutes are indicated in an original and refined way by means of two superimposed sapphire discs. The lower one forming the background features the celestial dome, the celestial time minute-track and the four cardinal points; while the second one placed on top bears the constellations, the projections of the equator (white circle) and the ecliptic (red circle) – the latter depicting the Sun’s annual trajectory as seen from Earth. This Lambert projection is an authentic scientific map corresponding to the constellations in the Northern Hemisphere.
The equation of time on tropical gear train
To measure and display the difference between civil and solar time, this timepiece is equipped with a complex and refined equation of time mechanism. Moreover, the latter is also a ‘running’ equation of time, a kind rarely seen in wristwatches and indicating solar time by means of an additional coaxial pink gold minutes hand adorned with a cut-out sun. The equation of time is generally displayed by a hand moving across an auxiliary sector with a scale running from +14 to -16 minutes and requiring a bit of mental arithmetic to check solar time. The running equation of time is far more complex to create and enables instant readings of solar and civil times. To ensure exactitude and precision, Vacheron Constantin has adjusted it to a tropical gear train simulating the tropical year, meaning the time the Earth takes to make a full turn around the Sun and corresponding to 365.2421898 days.
Time and tides
This unique creation features a doubled-sided display of 23 complications. On the front, the slate grey dial reveals 15 artfully arranged complications. As well as readings of civil and solar time (running equation of time) by three coaxial hands, it also has a perpetual calendar with a precision moon phase as well as a remarkable mareoscope composed of a tide level indicator and a 3D depiction of the Earth-Moon-Sun alignment. Tides are governed by physical laws and depend on the gravitational attraction and centrifugal forces of these three heavenly bodies.
Representing a ‘memory’ of time yet to come, a perpetual calendar is able to keep track of the irregularities of the Gregorian calendar with no need for any intervention other than a date change every 400 years. It displays the day of the week, the month and the leap-year cycle through apertures, while pointing to the date with a serpentine hand.
The fascinatingly elegant precision moon-phase display requires a one-day correction only once in 122 years and is read off by means of two superimposed discs bearing a laser-engraved true image of the full moon, a day/night indication and the age of the moon – meaning the number of days elapsed since the last full moon. These precious functions are complemented by sunrise and sunset times, pointed two by slim hands moving over two graduated scales, as well as the length of day and night appearing on a special gauge at 6 o’clock. This set of complications that occur but rarely in the Fine Watchmaking sky is further enriched by other captivating indications arranged in a semi-circle: zodiacal signs, seasons, solstices and equinoxes. Solstices – at which the day is at minimum or maximum length – occur twice a year in summer and winter; whereas equinoxes – when day and night are of equal length – correspond to the start of spring and autumn.
On the back of the watch, a second dial is also brimming with worthwhile astronomical functions. Composed of two superimposed sapphire discs, it is distinguished by its limpid, airy design as well as the originality of its translucent celestial chart for which a patent has been filed. In the foreground, this display depicts the constellation viewed from the Northern Hemisphere, ringed by an anthracite inner bezel ring showing the months of the year as well as a gauge-type power- reserve indicator. On this same transparent disc, two ellipses – one red and the other white – respectively correspond to the projections of the ecliptic and the celestial equator. Positioned beneath the constellation, a second disc rimmed by a graduated scale displays sidereal time and the four cardinal points, while an anthracite-coloured sphere reveals a see-through view of the celestial map. In addition, this innovative sky chart also provides a fascinating glimpse of the tourbillon at 6 o’clock.
A feat of technical sophistication and miniaturisation
To achieve Celestia, the Manufacture worked simultaneously on two fronts: by seeking to save energy on the one hand, and by increasing the size of its power supply. So as to optimise the energy stored as well as its transmission, the barrel springs are made from a sturdy and ductile Bioflex®* alloy, while the involute gears mesh in an ideal manner. Finally, the six barrels guarantee a substantial storage volume, while keeping the caliber as slim as possible. The resulting ensemble is a true feat of miniaturisation comprising 514-part finely adjusted and meticulously decorated parts and measuring just 8.7 mm thick! This unique mechanism, equipped with a tourbillon featuring a large balance wheel for enhanced precision and regularity, fits neatly inside an elegant 45 mm-diameter white gold case.
Like the entire Vacheron Constantin collection, Les Cabinotiers Celestia Astronomical Grand Complication 3600 bears the Hallmark of Geneva, confirming that it meets the numerous demanding criteria governing this prestigious quality certification.
The quintessentially rare Les Cabinotiers Celestia Astronomical Grand Complication 3600 is issued in a limited edition of one. Fitted with an alligator leather strap secured by a white gold pin buckle, it comes in a luxurious presentation box adorned with wood marquetry.