A highly technical single-piece edition, the Vacheron Constantin Armillary Tourbillon Perpetual Calendar ‘Planetaria’ watch stages sophisticated complications in a manner bearing a unique aesthetic signature. Equipped with a new Calibre 1991 in-house movement, this timepiece celebrates the astronomical function par excellence: the perpetual calendar with precision moon phases. With its retrograde date appearing along a right-hand arc on the dial, as well as its circular retrograde month and day indications framing depictions of the Earth’s two hemispheres providing day/night indications, this timepiece is also regulated by a double-axis tourbillon. This new model, presented at Watches & Wonders 2021, is part of the theme of the Maison for 2021 : entitled Classic with a Twist, it highlights Vacheron Constantin’s creative energy, guided by an identity that celebrates a heritage and dares to deliver the unexpected.

About the Calibre 1991 Grand Complication Movement

Extraordinarily complex with its 745 components, mechanical manual-winding Calibre 1991 is the result of a four-year development process. It powers two rotating globes representing the Earth's hemispheres, regulated by a double-axis Armillary tourbillon. It corresponds to an innovative interpretation of the perpetual calendar, the astronomical complication par excellence which "reads off" the specificities of the calendar without requiring any adjustments before 2100. Another distinctive feature lies in the retrograde displays of the perpetual calendar’s days, dates and months. Mounted on ball bearings to ensure smooth, linear operation, the date display follows a circular arc to the right of the hours and minutes dial. In keeping with the watch’s astronomical vocation, the center of the timekeeping dial bearing hour-markers is dedicated to the moon phases. These appear according to their respective evolution in the two hemispheres, in perfect symmetry with the two rotating globes, and with a degree of precision requiring a mere one-day correction every 122 years.

The perpetual calendar functions continue with the leap year appearing through a 5 o’clock aperture, along with circular day and month indications at 12 o'clock and 6 o'clock based on a jumping retrograde pallet-type display system. In the center of the two counters, the two globes representing the Northern and Southern hemispheres perform complete rotations in opposite directions on a graduated 24-hour scale around the rim. The shaded areas of the domed sapphire crystal used for the day/night indication have been positioned in such a way that the Armillary tourbillon resembles a sun darting its rays across the surface of the Earth.

Making the super-thin —0.35 mm— sapphire crystal featuring the domes and extending over the retrograde date display required a great deal of ingenuity. A crown-integrated pusher enables simultaneous adjustment of the world-time function of the two globes.

In an additional challenge for the movement's designers, who are consistently concerned with achieving optimal balance and aesthetic appeal, they had to imagine and design a retrograde system for the day and month indications leaving sufficiently ample space to admire the beating of the bi-axial Armillary tourbillon with its spherical balance-spring.

The complex mechanics of Calibre 1991 are perfectly epitomized in its Armillary tourbillon, a technical challenge as well as a spectacular sight in itself. This movement regulating device endowed with a 60-hour power reserve benefited from the research conducted on the world’s most complicated timepiece, Reference 57260. This construction is positioned on the left side of the piece, beneath the sapphire crystal ‘bubble’. Forming a sphere in perpetual motion, the tourbillon was named "Armillary" in reference to French watchmaker Antide Janvier, who towards the end of the 18th century invented a moving planetary sphere known as an Armillary, and regarded as one of his most accomplished masterpieces.

Another technical feature of the mechanism of this piece is the cylindrical balance-spring coupled with the balance. Invented by Jacques-Frédéric Houriet in 1814, this variant devoid of terminal curves gives the tourbillon a perfectly concentric beat, thereby ensuring enhanced isochronism. In order to transmit to this balance-spring the impulses corresponding to a frequency of 18,000 vibrations per hour —2.5 Hz—, Vacheron Constantin has developed an escapement consisting of a silicon escape-wheel and a lever with diamond pallets, materials reducing friction without any need for lubrication and thus increasing the precision of the mechanism.

Every single detail of the finishes gracing this single-piece edition highlights this ingenious astronomical orchestration of time. Two galvanically treated titanium globes weighing barely 0.12 grams rotate gently on the finely grained dial. The 24-hour counters surrounding them are circular satin-finished with transfers, while the day, month and date indications are printed beneath the sapphire crystal. The timekeeping dial features Roman numerals in the form of polished gold appliques. These Haute Horlogerie finishes are beautifully framed by an 18K 5N pink gold case measuring 46 mm in diameter and fitted with an alligator leather strap.

The Vacheron Constantin Les Cabinotiers Tourbillon Armillary perpetual calendar ‘Planetaria’ watch demonstrates technical mastery of watches featuring extreme astronomic and aesthetic complexity, with the integration on the dial of rotating globes. Equipped with the new manual-winding Calibre 1991 stemming from four years of development, this single-piece edition features a completely original perpetual calendar with a retrograde display of dates, days and months. This timepiece also offers a rare three-dimensional representation of the Earth’s Northern and Southern hemispheres. The two titanium globes perform a full rotation in 24 hours, complete with a day/night indication. The regulation of the movement is based on the same concern for technicality expressed by a double-axis Armillary tourbillon whose nested aluminum carriages move at a speed of 60 seconds per rotation. This timepiece is presented in an 18K 5N pink gold case measuring 46 mm in diameter, fitted with a dark brown alligator leather strap.

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