Photo: Louis Moinet

Mechanical watches sit high on the list of things you don’t need but will pay lots of money for. Astronomical complications are perhaps the most superfluous of them. There is no longer a practical need to know what phase the moon is in, much less the difference between solar time and mean time (also known as the equation of time).

And yet, millennia after our ancestors first started looking to the stars to make sense of the world, mankind is still captivated by what lies beyond the exosphere. 

Still, there’s a reason why watchmakers are still pouring hundreds of hours into designing such unnecessary indications — they are remarkably difficult to make. Astronomical timepieces, like minute repeaters and tourbillons, display a watchmaker’s horological prowess, allowing us to marvel at what human hands are still capable of.

And, of course, there is the undeniable romance of it all. Tracking celestial bodies was a way for people to navigate land and sea, predict harvest times, and measure the ebb and flow of tides. Once those mechanisms were miniaturised into pocket watches in the late 19th century, the quest to shrink them further continued, eventually giving us all a little piece of the universe we can wear on our wrists. 

Today, moon phase and calendar complications are common in haute horlogerie. But, a handful of watchmakers still go above and beyond (pun intended) to sate our innate desire to connect with the heavens.

Konstantin Chaykin Stargazer. (Photo: Konstantin Chaykin)

We don’t know if and when the Only Watch auction will resume, but that doesn’t mean we can’t still appreciate some of the mechanical marvels that were supposed to go under the hammer last year. One of these is the Konstantin Chaykin Stargazer, the most complicated watch ever made by the Russian brand.

Boasting 664 parts and 17 functions — 11 of which are astronomical — the Stargazer can even be worn double-sided thanks to special articulating lugs and a swivelling strap buckle. Especially unusual are the indicators for sunrise and sunset azimuths (a first for a wristwatch) and a solar activity cycle display. 

Christiaan Van der Klaauw Planetarium. (Photo: Klaauw)

The Christiaan Van der Klaauw Planetarium still holds the honour of housing the world’s smallest mechanical planetarium, indicated by a delicate orrery at 6 o’clock. It displays the real-time solar orbits of Mercury, Venus, Earth, Mars, Jupiter, and Saturn, with the golden orb in the centre representing the sun.

Probably the most famous example of this is the award-winning Planetarium Eise Eisinga, with a dial reminiscent of the actual Eise Eisinga Planetarium in Franeker in the Netherlands. The version pictured here is the SHH Edition of the Dunes of Mars model, with a rust-coloured aventurine dial mimicking the desert-like surface of the red planet. 

Louis Moinet Cosmopolis. (Photo: Louis Moinet)

Instead of complications, the Louis Moinet Cosmopolis pays tribute to the stars with a dial featuring slivers from 12 different meteorites that have been collected from around the world. 10 of these encircle the dial, all framed in gold, each with a unique history. The largest one in the centre is also the rarest — featuring a lunar meteorite that was found near Dhofar, Oman.

The last piece, a black chondrite that broke off from the collision between two asteroids, sits under the cage of the flying tourbillon at 6 o’clock. This one-off model is the current Guinness World Records title holder for “most meteorite inserts in a watch”. 

HYT Moon Runner. (Photo: HYT Watches)

HYT is best known for watches that tell time using coloured liquids that travel in hermetically sealed tubes, but including a three-dimensional moon phase in its Moon Runner line makes it look like something that belongs on the set of Apple TV’s Foundation.

For the Ghost and Desert models (named for their respective silvery and brown colourways), each moon is hand-painted in the dark by a master craftsman, working only by the light of UV lamps so that every detail faithfully represents what the human eye would observe at night, a painstaking process that requires an entire day to complete.

Bovet 1822 Recital 20 Asterium. (Photo: Bovet)

Winner of the Calendar and Astronomy Watch Prize at the 2023 Grand Prix d’Horlogerie de Geneve, the Bovet 1822 Recital 20 Asterium still enthrals even after almost seven years since its initial release. The exposed dial offers a host of information, including a sidereal calendar (which measures time based on the position of the stars rather than the sun), a constellation map, zodiac signs, solstices, moon phase, and an equation of time.

To top it all off, a patented double-face flying tourbillon revolves in the bottom half of the dial.