Vacheron Constantin’s Les Cavinotiers Solaria Ultra Grande Complication treats astronomy as a pure machine, which is why it won the 2025 Revolution Award for Best Astronomical Watch. This is not a star-spangled dial. It is a wrist-worn device that converts celestial phenomena into readable mechanically calculated representations. With 41 complications, it’s also officially the most complicated wristwatch ever made, but Solaria’s real achievement is in achieving celestial legibility across two dials.

Vacheron Constantin Les Cabinotiers Solaria Ultra Grande Complication La Premiere (©Revolution)

At its core is the 1,521-part Caliber 3655, which boasts five rare astronomical complications and an extensive suite of astronomical displays that go beyond the romance of moonphases to reflect the galaxy. Vacheron Constantin has clearly positioned four of these unusual features as being linked to the sun’s path across the sky, and the watch reflects that priority. Solaria does more than simply indicate “day” and “night”; it models the behavior of the sun in a way that requires actual mechanical calculations and presents it with a clarity that is unusual for something of this density.

Caliber 3655

The front focuses the “sun” intelligence at the 6 o’clock position. Here, Solaria visualizes the sun’s height above the horizon, the time of the sun’s zenith (true solar noon), the sun’s declination, and the equation of time, translating the discrepancy between mean solar time and apparent solar time into a representation that is the truth-telling definition of celestial truth in mechanical watchmaking. Around it, zodiacal and seasonal displays map the annual course of the sun, including the equinoxes and solstices, and are anchored to a miniature Earth dome and solar sphere whose relative positions represent declination in three dimensions. The sapphire ring surrounding the dial displays sunrise and sunset times and day length mechanically calibrated to a reference latitude, turning the watch into your personal daily planetarium.

“Sun” intelligence at 6 o’clock position (©Revolution)

Of course, astronomy is not just about the sun. Solaria weaves the moon’s gravity into the story via a malleoscope that tracks spring and neap tides. The very existence of this complication reminds us that the movements of the heavenly bodies have an effect on the earth. Then, when you turn the clock over, the night sky opens up. The Smoke Sapphire star map rotates in sidereal time (as opposed to stationary time), so the display is fixed on the stars rather than the sun. Most convincingly, Vacheron Constantin combined this celestial vault with a split-seconds chronograph to create the world’s first celestial time tracking feature. This allows the wearer to calculate when a selected star or constellation will appear in the center of the observer’s field of vision. In other words, the chronograph becomes an astronomical predictor.

The smoked sapphire star map rotates in sidereal time and the display is fixed to the stars (©Revolution)

All of this in a frankly impossible case. Measuring 45 mm in diameter and just 14.99 mm thick, it houses 1,521 components and is the result of eight years of development and protected by 13 patent applications. Solaria was awarded the Best Astronomical Clock because it embodies the ideal balance in the astronomical clock category: mechanical ingenuity useful for celestial interpretation.