The worlds of watchmaking and astronomy have long had symbiotic relationships—both, after all, rely on predicting the Earth's movement in relation to our celestial neighbours. The earliest clocks also relied on the greatest star of all—the sun.
Given this relationship, it seems only natural that watchmakers indulge in a little stargazing every now and then. It is this meditation on the stars that birthed Vacheron Constantin's latest celestial complication collection, the Métiers d'Art Copernicus celestial spheres 2460 RT.
The collection pays tribute to a model of the universe described in Nicolaus Copernicus' On the Revolutions of the Heavenly Spheres in 1543. Copernicus' book put forth the theory that the Earth is not at the centre of the universe, but actually revolves on its own axis and in an elliptical orbit around the sun. This heliocentric model of the universe was, and still is, one of humanity's greatest discoveries.
To illustrate this discovery in watch form, Vacheron Constantin created the mechanical self-winding calibre 2460 RT, which was designed, developed, and created in the brand's manufacture over the course of three years. It includes two complications, manifested in the form of a three-dimensional 'Earth' raised above the dial of the watches. The Earth rotates on its axis once every 24 hours, the same amount of time as a mean solar day.
Plus, a second complication allows the Earth to make one complete orbit around the sun in exactly 365.2421898 days, the length of one tropical year. This extreme precision means that the complication requires a one-day correction only once every 8, 000 years, which is no mean feat to achieve mechanically—proof of Vacheron Constantin's mastery over horological engineering.
Take a closer look at the Metiers d'Art Copernicus celestial spheres 2460 RT collection:
And although all three watches in the Métiers d'Art Copernicus celestial spheres 2460 RT collection bear the same movement, they all look completely different, thanks to Vacheron Constantin's use of métier d'art decorations. Each of the three watches comes with a dial crafted using a different métier d'art created by Vacheron Constantin's master craftsmen. The dials are all inspired by the design of the 17th century Harmonica Macrocosmica, an important and beautifully decorated map of the skies drawn by Dutch-German cartographer Anderas Cellarius.
At the centre of each dial rests a smiling picture of the sun, carved out of pink gold. But that's where the similarities end. The rest of the dials are decorated using different decoration techniques, namely champlevé Grand Feu enamel, hand-engraving on precious metals, and engraving on sapphire crystal.
The first technique, champlevé Grand Feu enamel, is done on a carved gold base. Numerous layers of pigment are meticulously laid down and fired at 850 degrees Celcius. The enamelling process here is made especially difficult by the 12 zodiac signs on the outer rings of the dial, which each have to be formed using stencils and finished with a quill pen before being filled in with a fine enamelling brush. Once we take into consideration that a portion of the dials will crack during the firing process, the amount of work that goes into this dial becomes even more apparent.
The second dial is completely carved out of white gold, with the 12 signs of the zodiac intertwined around each other. When viewed under a microscope, the incredible details of the hand-carving start emerge. The tight curls of the Taurus and the flowing mane of the Capricorn undoubtedly require a steady hand to be formed with such precision. Even the orbiting Earth has microscopic curlicues engraved onto the ocean areas to indicate the ebb and flow of their currents.
The final dial uses a novel technique, carving shapes into two different sides of transparent sapphire crystal. Given that sapphire crystal is usually prized for its scratch-resistant properties, the engraving process must have been no easy task. The shapes are first etched into the back of the crystal using an innovative laser technique, and a master craftsman then futher sculpts the raised motifs by hand. The front of the crystal is also laser-engraved with constellations before being daubed with glowing Super-Luminova. The crystal is laid over a hand-painted blue underdial to enhance the contrast and three-dimensional qualities of the sapphire crystal dial.
The watches in the Métiers d'Art Copernicus celestial spheres 2460 RT collection are not only the result of years of research and development into actually making the timepieces, but also of centuries of human inquiry into the nature of our universe.
And that, perhaps, is the most satisfying part.