acheron Constantin celebrates its 270th anniversary and its enduring quest for excellence with a new series of Les Cabinotiers watches entitled ‘La Quête’, which pays tribute to astronomy and the odysseys of ancient times. Representing significant technical and aesthetic challenges, these watches highlight Vacheron Constantin’s expertise in the creation of grand complication watches enhanced by the artistic crafts.

The Les Cabinotiers Armillary Tourbillon – Myth of the Pleiades watch refers to the ‘Seven Sisters’ of Greek mythology, which were transformed into stars in the constellation of Taurus and served as a vital navigation point for sailors in ancient times. These themes are represented by intricate hand-engraving on the case sides. The watch is equipped with Calibre 1990, a manufacture movement protected by four patents and incorporating a bi-axial tourbillon and bi-retrograde time indications.

The observation of the stars, the cycle of the seasons and the alternation of day and night have always aroused human curiosity, and from very early times, mankind sought to model these phenomena. Thanks to the first astronomical observatories, space-time became a more concrete concept, explained in terms of measurable cycles. This deep urge to decipher one’s environment is also expressed in the epics of ancient times, led by great conquerors such as Alexander the Great and Genghis Khan, and inspired by myths and legends ranging from the Pleiades to the 12 Labours of Hercules.

In Greek mythology, there are seven Pleiades, daughters of the Titan Atlas and the Oceanid nymph Pleione. Pursued by the hunter Orion for seven years, they are saved by Zeus, who grants them immortality by transforming them into a constellation in the celestial vault. But it was all in vain, as Orion invaded the starry sky, prompting Zeus to intervene once again by placing Taurus, the celestial bull, with its menacing horns between the Pleiades and the hunter. Seen as the sentinels of the sky, serving as navigational reference points on ancient maritime routes, they acquired a mythological dimension. The discovery of the Pleiades, already marked on the Nebra sky disc in 1600 BC and mentioned in Homer’s Iliad and Odyssey eight centuries later, illustrates man’s inexorable desire to master space-time.

The Les Cabinotiers Armillary Tourbillon – Myth of the Pleiades watch is equipped with Calibre 1990, a hand-wound manufacture movement born from the technical advances of the Reference 57260. It features a bi-retrograde display of the hours and minutes, with the instantaneous return of the hands to zero at midday and midnight. Because the mechanism is subjected to strong forces, meticulous attention was given to the choice of materials used, to ensure the accuracy of the display. For the hands, titanium was chosen for its superior lightness and strength compared to steel. The retrograde time display is indicated on a semi- circular track marked with Roman numerals for the hours and Arabic numerals for the minutes. With the time indication set on the dial flange, a portion of the dial is open, revealing part of the movement and thus reinforcing the technical aspect of the watch.

Four patents mark the technical innovations of the Calibre 1990.

• The instantaneous retrograde system, controlled by the minute cam alone, which synchronises the jump of the two hands at midnight or midday.

• The escape wheel collet – this component, which secures the inner end of the balance spring, is made of titanium because the light weight of the material is compatible with those used in the regulating organ, resulting in optimal isochronism of the regulator.

• The architecture of the tourbillon cages, which, as they rotate, form a Maltese cross pattern every 15 seconds, representing the emblem of Vacheron Constantin.

• The titanium lever with diamond-coated pallets, ensuring increased wear resistance and an optimised coefficient of friction.

The dial layout, with bi-retrograde time indications on the right, leaves the entire left side for the armillary tourbillon. Animated by two axes of rotation, its mechanical ballet is displayed under a dome on the sapphire crystal at 9 o’clock. The name armillary refers to the work of the 18th-century French watchmaker Antide Janvier, inventor of a moving sphere that enabled him to explain the apparent movements of the stars. Visually, this tourbillon evokes the graduated circles of armillary spheres – the 18th-century scientific instrument used to determine the coordinates of the stars in the era of pre-telescopic astronomy. Also serving as a small-seconds display, the regulator comprises two aluminium cages nested inside each other and rotating on two different axes at a rate of one rotation per minute, forming a sphere in perpetual motion.

The tourbillon is equipped with a spherical balance spring. Invented by Jacques-Frédéric Houriet in 1814, this type of balance spring has no terminal curves and remains particularly rare in contemporary watchmaking. Extremely difficult to produce, it requires micron-level precision, an expertise possessed by very few craftsmen. This hairspring gives the tourbillon a concentric beat, which ensures better isochronism and therefore greater precision. To transmit the impulses, timed at 18,000 vibrations per hour (2.5 Hz), Vacheron Constantin developed an escapement with a titanium anchor and diamond pallets. This choice of material reduces friction without requiring lubrication, thus ensuring greater reliability of the mechanism. The use of high-tech materials, with a reduction in weight as a bonus, contributes to the chronometric performance of this escapement, which meets the requirements of the Swiss Official Chronometer Testing Institute (COSC). This is all the more notable because the instantaneous bi-retrograde mechanism requires a large amount of torque throughout the 60-hour power reserve.

The technical sophistication of the calibre is matched by the attention to detail and finish. On the front, the open-worked dial reveals bevelled and polished components. The main plate, crafted from nickel silver and coated with a t tone obtained through a specific treatment, features a circular satin finish, while the bridges and dial share the same metal, enhancing the visibility of the blue minute track. The blued screws and bi-retrograde hands add a touch of depth to this kinetic composition. The case back offers a view of the hand-bevelled bridges decorated with horizontal Côtes de Genève, with blued screws creating contrast.

The designers and master engravers at Vacheron Constantin were inspired by the work of the Polish astronomer Johannes Hevel (1611–1687), known as Hevelius, who, in addition to mapping the Moon, discovered numerous comets and compiled an exhaustive catalogue of stars. Hevelius also produced one of the first accurate star atlases, linking the constellations to mythological figures in a structured way. Richly illustrated with many of his own engravings, it inspired the decoration of this watch dedicated to the Pleiades.

The engraving on the crown side of the case depicts a cloudy sky from which Orion, sword and shield in hand, emerges ready to do battle to conquer the Pleiades – the stars protected by the bull sent by Zeus. On the other side of the case, the ship Argos, described as an ancient constellation by Ptolemy (circa 100–168), bears an image of the protective goddess Athena on its sail. In search of the Golden Fleece, Argos sails across waves populated by sea monsters, chimeras and dolphins, using the Pleiades of the constellation Taurus – represented in the style of Hevelius – as a navigational beacon.

To create these compositions on the 20 mm high case, the engraver first draws the outlines of the silhouettes, stars and clouds using drypoint, a painstaking task given the profusion of detail. The next step is to bring out the volumes with a burin, working by removing material, while ensuring that the incisions do not exceed 1 millimetre in depth. Then begins the micro-sculpting work, which gives the final appearance to the hunter Orion, the bull Taurus and the clouds on one side of the case, and the sea creatures, the ship, the waves and the bull’s head on the other. To achieve the extreme precision required by these compositions, the burins must be sharpened multiple times. As the carving progresses, the detail is constantly refined to bring out the slightest relief and plays of light are created by alternating surface treatments. To create the striking spectacle on the crown side of the case, the engraver uses this technique to bring out Orion’s shield and the bull’s legs and horns.

Working in collaboration with the gem setter, the engraver simultaneously determines the locations of the 10 brilliant-cut diamonds representing the Pleiades, placing each stone at the exact height to represent the stars. In fact, the Pleiades, numbering seven in mythology, represent an open cluster of 3,000 stars in the constellation of Taurus but only 10 are visible to the naked eye. The diamonds, in two different sizes (0.6 and 0.9 mm), are bezel-set: six diamonds dot the sky on the crown side, while the remaining four, on the other side of the case, are set within the sculpture of Taurus. Once the gem-setter’s work is complete, the engraver finalises the surfaces of the sky and its constellations using drypoint technique, alternating between polished and chased finishes to accentuate contrasts. The engraver took the ornamentation to the maximum by decorating the space between the horns with three constellations located around the Pleiades (Aries and Musca at 12 o’clock, Gemini at 6 o’clock), using taille-douce engraving with chased finishes to accentuate the contrasts.

The bezel, lugs and caseback feature a wave- shaped champlevé engraving in the Hellenic style. To ensure that the pattern is uniform, the engraver first traces the contours of the design in drypoint. He then incises the pattern to a depth between 0.1 and 0.2 millimetres to bring out the contours. Making the exercise even more complex, some of the areas to be engraved, particularly on the case back, are extremely thin. The engraver then accentuates the pattern by chiselling the hollows and polishing the ridges, yet another challenge, given how fine the lines are. In total, it took the engraver 450 hours to complete his work.

TECHNICAL SPECIFICATIONS

ARMILLARY TOURBILLON – MYTH OF THE PLEIADES

REFERENCE 9890C/000R-273C

• Certified by the Hallmark of Geneva

CALIBRE 1990

• Developed and manufactured by Vacheron Constantin
• Mechanical with manual winding
• 35.50 mm diameter, 10 mm thickness
• Movement power reserve: approximately 60 hours
• Frequency: 2.5 Hz (18,000 vibrations/hour)
• 299 components
• 45 jewels
• ‘Soft champagne’ finish, bridges decorated with Côtes de Genève, circular satin-finished plate

INDICATIONS

• Retrograde hours and minutes Small seconds on tourbillon Armillary tourbillon

CASE

• 750/1000 4N pink gold, hand-engraved and set with 10 brilliant-cut diamonds (approx. 0.02 ct, IF-VVS, D-G) 45 mm diameter, 20.13 mm thickness
• Transparent caseback with sapphire crystal
• Water resistance tested to a pressure of 3 bar (approx. 30 metres)

DIAL

• 4N pink gold colour with sunray satin finish, circular satin-finished hour markers and minute track Blue titanium hands

STRAP

• Dark blue Mississippiensis alligator leather with alligator leather lining, hand-stitched, saddle-stitched finish, large square scales

CLASP

• Hand-engraved 4N 750/1000 pink gold folding clasp
• Case & accessories Les Cabinotiers model