vacheron constantin’s ‘most complicated wristwatch ever’ tracks both standard and solar time

unveiling les cabinotiers solaria ultra grand complication

At Watches & Wonders 2025, Vacheron Constantin has unveiled its most intricate and technical timepiece yet — Les Cabinotiers Solaria Ultra Grand Complication. As ‘the most complicated wristwatch ever made,’ according to the Swiss luxury watchmakers, this one-of-a-kind timepiece is developed as a miniaturized observatory — bringing together 1,521 handcrafted components under the newly developed Calibre 3655.

Crafted in 18K white gold, the watch’s case measures 45 millimeters in diameter and 14.99 millimeters in thickness, housing 41 complications, 5 rare astronomical functions, and an innovative Westminster minute-repeater. These extensive functionalities are brought together in a double-sided display to integrate three modes of timekeeping: standard civil time, true solar time accounting for the Earth’s elliptical orbit, and sidereal team based on Earth’s rotation relative to fixed stars. In addition to tracking the passage of time, the Solaria provides real-time data on the sun’s position, culmination, and declination, as well as the ability to pinpoint the appearance of celestial objects.

all images courtesy of Vacheron Constantin

vacheron constantin integrates three modes of timekeeping

Since introducing its first watch with a date calendar complication in the late 18th century, Vacheron Constantin has continued to advance the art of mechanical watchmaking, particularly in the field of astronomical complications. The Les Cabinotiers Solaria Ultra Grand Complication follows this tradition, offering a sophisticated exploration of time through the lens of celestial mechanics. The timepiece operates on three distinct timekeeping systems that operate simultaneously, each with its own dedicated gear train. On the front dial, the watch displays civil time — the 24-hour standard based on International Atomic Time, used across the world. Its hour and minute hands are complemented by a second time zone.

The reverse side shifts focus to sidereal time, measured against the fixed stars. Minutes are marked on the periphery of the sapphire crystal caseback, while hours rotate beneath it on a moving disc. The third system is devoted to solar time, which reflects the true length of a day as influenced by Earth’s elliptical orbit. Because the actual solar day varies from -16 to +14 minutes over the course of a year, aligning with civil time only four times annually, this difference is displayed on a subdial at 6 o’clock.

advanced astronomical complications

Vacheron Constantin distinguishes the Les Cabinotiers Solaria Ultra Grand Complication with five advanced astronomical complications, four of which track the sun’s movement across the sky. Through a highly intricate mechanism, the watch displays the real-time position of the sun, its altitude, its culmination time, and its declination angle. The fifth complication is a world first, combining a split-seconds chronograph with a celestial vault representation, which allows the wearer to calculate the time it takes for a specific constellation or star to appear centered in their field of vision.

The front dial organizes its four subdials with clarity, two of which each display up to five separate functions. A monochromatic palette of black, white, and grey enhances contrast, with refined sunburst, sandblasted, and circular satin-polished finishes ensuring depth and readability. The 6 o’clock subdial adds a sculptural element with its 5 millimeter rhodium-plated gold Earth dome, featuring polished continents and sandblasted oceans, while a gleaming 18K yellow gold hemisphere represents the sun’s declination. The reverse side transforms into a celestial chart, mapping constellations, the equatorial and ecliptic ellipses, months, and a 60-second scale. A rotating metallized disc in dual shades of grey showcases the celestial vault and a 24-hour scale, with lacquered split-seconds chronograph hands in green and red.