Vacheron Constantin

In 2016, Vacheron Constantin created the most complicated timepiece ever, the 57260 pocket watch, featuring 57 complications. It caused a stir in the horological industry.

This year, the company has doubled down, introducing its most complicated wristwatch, the Les Cabinotiers Celestia Astronomical Grand Complication 3600, with 23 complications.


One would assume these two developments had to have been connected - symbiotic, even. But the truth is, they were both developed in secret, with neither development team even aware of the other's existence.

The Celestia was made to honour the way the grand watchmaking masters worked, according to Christian Selmoni, Vacheron Constantin's artistic director. "They were developing something that reflected their new ideas, without regard for the time required," he says. "In almost all other watchmaking brands, this kind of spirit doesn't exist - we always tend to reuse something to save time. Developing movements just for one piece is unique. This timepiece was created in the spirit of the historical astronomical clocks with extraordinary levels of precision, and that makes the Celestia very important."

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The Celestia, the brainchild of a project head, master watchmaker and conceptor (of whom Vacheron Constantin would not release his name for fear of being poached - he will from here on be referred to as "MW"), is part of a relatively recent programme inside the Les Cabinotiers ("the Artisans") department. Its aim is to develop unique "blue sky" timepieces while undertaking its raison d'etre, bespoke work. MW has had a lifelong interest in astronomy, and astronomical indications are at the Celestia's core.

"Astronomy is a very serious science as is watchmaking. Without astronomy, we wouldn't be able to measure time - it's all dependent," MW explains. "Our ancestors were reading the time with the stars, the Sun and the Moon, and the origins of watchmaking come from astronomy."


According to MW, mathematics was at the very heart of the Celestia's development. "The initial idea is to think about the concept of the watch, then to work out the equations to make it a reality," he explains. "I spent a year conceiving the watch and working on the mathematical equations, then I had to transform the mathematics into gear trains to provide the indications.

The Celestia's rear display has a celestial chart indicating sidereal time Vacheron Constantin

"For example, if I want to make a wheel turn, I have to calculate the number of teeth on the wheel. All the other wheels depend on this equation, so I need to be able to understand the principles, even though I have the software," he says. "No software can give me the answers. I rely on these equations and the powerful software to find a solution with our input. It's a question of using these tools to find new solutions."

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The Celestia's development took five years - three of which were dedicated to conceptualisation, including mathematical work, then it took two years to fabricate the watch itself. Not every company would allow this kind of development, but Vacheron Constantin, as the oldest continuous-watchmaking maison in the world, feels a responsibility to push horology forward.


"We have an obligation to advance watchmaking with our developments," MW says. "For example, we do an astronomical Moon phase that also incorporates a coaxial day/night indicator, based on the solar gear train. For the Moon phase display, a 3D Moon is engraved on a superimposed sapphire crystal disc, which is also linked to the solar gear train. We have a figurative perception of the Moon in the sky, and it is much more precise than most normal Moon phases. We could do something very simple, but that's not what our department's mission is."

The most challenging piece of the Celestia's puzzle was the running equation of time, a display that shows the difference between apparent solar time (true solar time, the actual solar day) and mean solar time (for all intents and purposes, civil time). Usually, the equation of time is displayed using plus or minus relative to normal civil time (this can be ahead by more than 15 minutes or behind by as much as 14 minutes throughout the year).

"The running equation of time in the Celestia is not linked to the perpetual calendar because that would not be precise enough," MW explains. "We developed one gear train that's linked to the solar indications, and the equation of time is driven by this dedicated tropical gear train, with a precision of approximately 150 years. This is much more precise than the perpetual calendar gear train."

The important specs Price $1 million Size 45mm Movement Mechanical manual-winding

Equipping this watch with an extra-long power reserve was also important to MW and Vacheron Constantin. The standard power reserve for watches is 48 hours or so, but the company realised this would not be enough for such a complicated timepiece that is very intricate to set correctly should it wind down. As a result, MW incorporated an almost five-metre long mainspring, in six barrels, to obtain a 21-day power reserve in keeping with the spirit of those early astronomical clocks, which needed to be wound every two weeks or so.


The Celestia is the most complicated wristwatch Vacheron Constantin has ever made, but from a distance, one would never know - which was the point from the very beginning. MW wanted to create a wearable watch, so he built the integrated movement from scratch, aiming for a timepiece thin enough to wear every single day.

In fact, making it as thin as possible was so important that when MW thought of a way to save 0.2mm, it required a rethinking of the entire gear train. "This is usually never done - once you have the gear train, the technical department would prefer not to touch it again, but we decided to completely rethink it," he says. "The flexibility to recreate the entire movement ourselves gives us the freedom to do it any way we decide is best."

Though the initial Celestia is a unique piece, and has already been sold for an estimated $1 million (£806,000), the brand plans to use this as a base for future customer orders - as long as each iteration remains unique. And some of the developments within the Celestia could quite possibly find their way into other timepieces in the future. After all, the secrecy is over, so Les Cabinotiers are happy to share it all with the rest of the company.