Astronomy and Watchmaking

Astronomical displays are rare, technical complications, and in recent years they’ve become part of the core expertise of independent brands – which have lost no time in giving the genre a thorough overhaul. Here’s a look at this celestial universe, from F.P. Journe to De Bethune via Patek Philippe.

“Watchmaking is the daughter of astronomy.” So says historian Dominique Fléchon, echoing a sentiment expressed by many successive generations of watchmakers. And indeed, both disciplines involve measuring time. In watchmaking, doing so enables human beings to be synchronized with one another. In astronomy, time is measured to calculate the speeds and hence the positions of heavenly bodies, the composition of galaxies or planetary systems, and so on. Watchmaking and astronomy thus share the same foundation but are used for different aims: in the case of astronomy, to advance science; and in the case of watchmaking, for social purposes.

As a result, these two fields have progressed in parallel; the major difference is one of scale. Watchmaking works with seconds, hours, days, months, and at most, centuries, while astronomy works in terms of billions of years.

The Universe in Three Square Centimeters

That said, their paths do cross occasionally. Watchmaking often likes to think of itself as scientific, attempting to encapsulate the immensely large in something much, much smaller – the solar system in three square centimeters of dial space, for instance. That may well be madness, but it’s poetic madness.

When it comes down to it, fitting the universe into a watch is perhaps not so much a problem of scale as one of precision. To remain accurate and not seize up, watchmaking mechanisms have to operate on a regular basis, whereas some planets take several decades to rotate; no gear train can stay immobile for timescales of this magnitude, start moving again, and work as it was intended to. Watchmakers are thus constantly striving to design a movement that’s as accurate as possible – and then moving on to try again with the next version.

Sovereign For a Day, Sovereign Forever

Despite these limitations, watchmakers have by no means given up on the task; take François-Paul Journe. He presented the first version of his Astronomic Souveraine at Only Watch, followed a few months later by his final version – after six years’ worth of research and development. This Grande Complication features sidereal hours and minutes, Moon Phases, an annual calendar, equation of time, sunrise and sunset, and zodiac cycles. 758 components in a 44mm case? It’s the universe in a thimble.

The Master of the Stars

While this particular complication is rather unusual for F.P. Journe, the same cannot be said of Christian Van der Klaauw; the universe is his home ground. As a bare minimum, each and every one of his creations sports a Moon Phase, a habit he’s been refining ever since 1974. It’s no accident that Christiaan van der Klaauw was born in Leiden, the city where Christiaan Huygens, one of the greatest scientists of all time, began his studies in 1645. Like F.P. Journe, Van der Klaauw studied at the Sterrewacht Leiden – the oldest university observatory in the world, founded in 1633 – and is a member of Académie Horlogère des Créateurs Indépendants (the Academy of Independent Creators in Watchmaking)

Deciding which Van der Klaauw watch to talk about is a tough one: they’re all astronomical complications! His original creation included an amazing feature: no matter when you glance at the watch, the dial indicates the place on Earth when it’s exactly 12 noon just then. Or there’s the smallest planetarium in the world. And what about the watch produced with Van Cleef & Arpels that won a GPHG prize in 2018? The fact is that to date, Christiaan van der Klaauw Astronomical Watches is the only workshop in the world fully devoted to the design and production of hand-made astronomical timepieces.

Code Name DB25

Over at De Béthune, a smaller part of the night sky has become a core component of the brand’s identity: the Moon, albeit an abstract interpretation thereof – a perfectly circular, two-tone disc standing out from a heavenly background made of gold dust. The Moon has been a constant feature from the 2004 DB15 onwards, becoming an established feature in 2010 with the latter’s successor, the DB25.

Reconciling Astronomy and Watchmaking

Urwerk is another independent that’s made a name for itself with an unusual complication, found today on the UR-100. Once the minutes hand has passed the sixtieth minute, it disappears and then reappears as an odometer, depicting the 555 kilometres travelled by every person on Earth once every 20 minutes, corresponding to the Earth’s average rotation speed at the Equator. Opposite this, the rotation of the Earth itself around the sun is displayed: 35,740 kilometres every 20 minutes. On the face of the UR-100V, hours and kilometres share the same status, and the same scale – it’s a place where watchmaking and astronomy collide.

Complex Yet Simple

The most recent Blast Moonstruck by Ulysse Nardin is more technical in nature. The watch displays a Moon Phase, the positions of the Sun and Moon around the globe as observed from Earth, and a tide indicator – but its real achievement is to make all this clear, readable, and intelligible. The inventor of this extremely simplified, understandable complication is the multi-talented genius Ludwig Oechslin.

Patek Philippe: Heavenly Art

Meanwhile, Patek Philippe, another independent firm, has hewn as closely as possible to the etiquette of traditional fine watchmaking. Its iterations of the astronomical watch are rare and exceptional, the most recent being the Grande Complication 6002R, while its second-most complicated wristwatch is the Sky Moon Tourbillon (Ref. 5002), launched in 2001. This rare, double-face piece features a Moon Phase as well as sidereal time and a star chart, on which the apparent movement of the Moon and stars in the northern hemisphere is displayed.