Very big news last year, in every possible sense of the word, was Vacheron Constantin's launch of the ref. 57260 pocket watch, the most complicated watch in the world. It had myriad complications, many astronomical in orientation, and some quite unusual (including a lunisolar Hebraic perpetual calendar). For 2017, Vacheron Constantin has announced a new highly-complicated watch; this time, however, it's a wristwatch, which focuses on astronomical indications in a very pure way. This is the Les Cabinotiers Celestia Astronomical Grand Complication, and it's the most complicated wristwatch Vacheron has ever created.
We'll be going in depth on this one soon, but for now, here's what we have for you: this is a unique piece, with a complete suite of astronomical complications. It is housed in a white gold case measuring 45mm x 13.6mm. The movement is designated caliber 3600 and it's 36mm x 8.7mm with six mainspring barrels offering a three-week power reserve (which is quite a feat in a watch this relatively small and with this many complications).
In addition to the time, you also have a moonphase, a sunrise/sunset complication, an indication of the length of the day and night, and a sector showing the current Sun sign in the Zodiac, as well as the Equinoxes and Solstices. You'll notice a golden hand with a Sun at its tip, in addition to the hour and minute hands – this is an Equation of Time marchant (we'll get into what that is shortly). Also on the front of the watch is a full, instantaneous perpetual calendar with leap year indication. Also on the front of the watch is something very much off the beaten path: a so-called Mareoscope, which shows the relationship of the Sun, Moon, and the tides as well.
On the back of the watch we have even more. This is where, in both pocket and wristwatches with astronomical complications, you would usually find a star chart if you were going to find one at all, and that's where VC quite logically put one as well. The sky chart is made of two separate disks of sapphire, and it shows the stars currently above the horizon, the position of the Milky Way, sidereal time, the tourbillon (which is not a complication per se but there it is if you're looking for it), indications showing the location of the celestial equator and plane of the ecliptic, and, on the far left, an unusual gauge-like power reserve.
Let's take a closer look at a few of these.
Sunrise/Sunset And Length Of Day Indication
If you follow the evolution of complications and you've come into watches relatively recently, you might think of the sunrise/sunset complication as unusual but not especially ground-breaking. It's surprising therefore to hear that, in wristwatches, it's a pretty new complication. The very first wristwatch with the complication was from Audemars Piguet: the Jules Audemars Equation Of Time, (a.k.a. the Most Interesting Watch You Probably Forgot About) which came out in 2000. It was followed by the Eos Sunrise/Sunset watch, by German watchmaker Martin Braun (a.k.a. The Most Interesting Watchmaker You Probably Forgot About), and though it has since cropped up here and there, it's still pretty rare.
This is mostly due to the fact that times for sunup and sundown are specific to latitude, which means every watch is basically a custom order as you have to make the cams that control the movement of the hands for each individual watch depending on the location desired by the owner. I'd assume the same latitude specificity applies to the length of day indication as well; you'd need a different disk for each latitude (the indication of sunrise and sunset on the VC Celestia changes thanks to the rotation of a bi-colored disk hidden behind the slit on the dial).
Equinoxes, Solstices, And Signs Of The Zodiac
This one is relatively straightforward. The disk carrying both the signs of the Zodiac (we'll leave aside the fact that the constellations representing the Zodiacal signs have drifted out of alignment with where they are said to be in traditional astrology) and the Equinoxes and Solstices (which, to drastically oversimplify, mark the divisions between the seasons) makes one revolution per tropical year (the time it takes for the Earth to take one trip around the Sun, as observed from the Sun's position in the sky as seen from Earth, as opposed to a sidereal year, which uses the stars as an observational reference).
The indication of the Equinoxes is approximate, it can vary from year to year by several days. Still, as a general way of staying in touch with where you are seasonally, this is more than adequate.
As tempted as I am to make a (very bad) pun that a Mareoscope complication is one that lets you know the location of a certain famous video game plumber with a strong Italian accent, I will refrain. The Mareoscope is basically an indication of the phase of the Moon, integrated with a tide chart. I'm not sure if the term is older than modern watchmaking (I've never seen it before, but that doesn't mean anything) – the only other use of the term I can find is in, of all things, a vintage Eberhard chronograph with a "mareoscope" indication, which is definitely much simpler. The general idea here is pretty clear: the Moon rotates around the Earth once per month, so you can see the configuration of the Sun-Moon-Earth system. This affects the height of the tides, which you can see from the tidal height indicator. It's a quite beautiful little system, and it pairs very well with the perpetual calendar, which is based on the position of the Earth in its orbit around the Sun.
The Equation of Time 'Marchant'
The equation of time in a wristwatch has become a somewhat more common complication in the last 16 or so years but it's still relatively rare, partly due to the fact that it's a somewhat abstract complication in several respects. The complication is based on the fact that our standard 24 hour day is actually an average of the time it takes for the Sun to return to the same position in the sky (which is how you mark off a solar day). That time can vary by as much as a quarter of an hour or more over the course of a year, and the equation of time is just the difference on any given day, between the length of that particular solar day, and the mean, or average, solar day.
Generally the equation of time is shown by a hand that shows how many minutes you should add or subtract from mean solar time to get the actual local solar time. This requires a little addition or subtraction but in their desire to spare clients inconvenience, watchmakers came up with the equation of time marchant, in which the amount of time ahead or behind is shown by a continuously running hand that slowly oscillates ahead or behind the minute hand as the year goes by.
The Back: A Star Map, Showing Stars Above The Horizon, The Celestial Equator And Plane Of The Ecliptic, Relative Position Of the Milky Way, Sidereal Time, And Power Reserve
There is quite a lot of information you can get out of the back of this watch. At its most basic, this is a mechanically driven planisphere. A basic planisphere is something any of you who had an interest in backyard astronomy might be familiar with – that cardboard gadget consisting of two disks, with the bottom one printed with the stars, and the upper one with a cutout in it, whose edges represent the horizon, and within which you can see which stars are above the horizon at any given hour. The planisphere of this watch likewise consists of two disks. The upper one is printed with the stars, as well as a red and white ellipse. The red one represents the position of the Plane of the Ecliptic; this is the plane in which the orbits of the planets lie. As seen from Earth, it looks like a curve cutting across the sky, along which (more or less) the planets appear to move. The white one represents the Celestial Equator, which is a projection of the Earth's equator onto the celestial sphere.
The disk's also got a representation of the Milky Way on it, which you can (if there is not too much light pollution) also see passing across the night sky.
The lower disk rotates once per sidereal day, so placing a hand on it (or in this case, a golden triangle) gives you, hey presto, a sidereal time indication. The black ellipse shows you what stars are rising above or sinking below the horizon at any time.
You may notice that the whole system rotates around a central pivot, and exactly on that pivot is a star. Its official name is Alpha Ursae Minoris and it is the last star in the tail of the Northern constellation known as the Little Bear. It is better known as Polaris – the only star that does not move in the night sky, as it is directly on the projected axis of the Earth's north pole, making it the star to observe when you're observing stars for latitude (there is no corresponding Southern star, which means navigators in the Southern Hemisphere had to devise other means, such as those developed by ancient Polynesian navigators).
The movement is remarkable for its small size relative to the complexity of its indications, but also, relative to its power reserve. The different indications are rooted in just three basic time systems: civil time (mean solar time), local solar time (the Equation of Time), and sidereal time. The first two mark the passage of a day based on the position of the Sun, while the latter does so based on the position of the stars. Thanks to the nearness of the Sun relative to the distant stars, an observed solar day is slightly shorter than an observed sidereal day and there are separate gear systems for all three systems in the watch.
The power reserve of three weeks would ordinarily require a pretty cumbersome mainspring barrel, or series of barrels. Though there are six barrels in the Celestia, they're kept relatively flat, partly thanks to the use of an alloy for the mainsprings called Bioflex, which as it turns out, is one of the so-called "shape memory" alloys. This is a group of alloys that gets their name from the fact that if deformed, application of heat can make the sample return to its original shape. In this application, they're being used for their high elasticity and resistance to deformation over time (features that make them useful in medical applications as well).
One of the loveliest things about this watch, I think, is that it really focuses on astronomical complications exclusively. It's an enormously appealing piece both intellectually and aesthetically. The great Breguet collector, Sir David Salomons, famously wrote that to carry a Breguet is to feel you have the brains of a genius in your pocket (which would up your dry cleaning bill, but one takes his point). I think wearing this watch would make you feel you had the universe on your wrist, and all the more so for finding so many ways to look at the heavens.
Les Cabinotiers Celestia Astronomical Grand Complication 3600: ref. 9720C/00G-B281, with Geneva Hallmark. Movement, caliber 3600, hand wound, 36mm x 8.7mm, three week power reserve from six mainspring barrels. 18k white gold case, 45mm x 13.6mm, 3 bar water resistance. Slate dial with 18k gold hour markers. Price approximately $1 million.