The Jaeger-LeCoultre Master Grand Tradition Grande Complication ‘Céleste’
A high water mark for complicated watchmaking from the watchmaker’s watchmaker.
The Master Grand Tradition Grande Complication Céleste was introduced by JLC in 2010 and it represents a benchmark for complicated watchmaking, from a watchmaker whose movements and complications have distinguished not only its own watches but those of the many other brands who have used their movements, both simple and complicated. Ultra-complicated watches from Jaeger-LeCoultre are still very much present in their catalog in the Hybris Artistica and Hybris Mechanica collections, but JLC has been specializing in making highly complicated timepieces, and grand complications, for many decades. Even the Reverso case has been used to house ultra-complex timepieces, like the Reverso Grand Complication À Triptyque.
In 2010, JLC introduced the first version of the Master Grand Tradition Grande Complication Céleste, which despite the company’s long history of complicated watchmaking, was unlike anything it had ever made. The watch is an orbital flying tourbillon, with an indication for sidereal time, a star chart, and a 24 hour indication as well as indications for the month, and for the position of the Sun in the Zodiac over the course of a year. The watch on top of everything else is also a minute repeater. Repeaters are already the most exotic of complications and they have, unlike the other two complications traditionally considered part of a grand complcation, resisted industrialization; the JLC repeater mechanisms in this watch include sapphire gongs with the foot welded to the underside of the crystal, and JLC’s so-called “trebuchet” hammers, which have internal springs intended to improve energy delivery to the gongs, and reduce recoil. The gongs weren’t the usual hardened steel gongs usually found in a minute repeater – instead, they were made of synthetic sapphire, square in cross section to improve energy transfer from the hammers, and welded to the underside of the crystal, so that the sound radiated directly from the crystal outward, rather than having to travel through the movement, dial, and case.
The Orbital Tourbillon
The first thing you notice about the watch – and there is a lot to notice – is the orbital flying tourbillon. The flying tourbillon is usually said to have been invented by Albert Helwig, at the Glashütte School Of Watchmaking, in 1920 although there is pretty solid evidence that what is technically a flying tourbillon – albeit different in design from Helwig’s – was actually invented by the English watchmaker, Robert Benson North, who filed a patent for his invention some fifteen years before Helwig.
The flying tourbillon is so called because unlike conventional tourbillons, there is no upper tourbillon bridge – the JLC orbital flying tourbillon rotates around its own axis once every 60 seconds, and therefore can act as a sort of field-expedient seconds hand. It also rotates around the center of the dial, once per sidereal day – that is, one orbit every 23 hours, 56 minutes, and 4.09 seconds, which is usually rounded up to 4.1 seconds for convenience (not, however, by astronomers, for whom precision is paramount; the closer figure is 23.9344696 hours, with the seconds derived from the Standard International second, which is in turn derived from the vibrations of a cesium atom in an atomic clock – we won’t go there right now.) The tourbillon sits above the dial, so the hands of the watch have to stand high enough above the dial to clear the tourbillon.
The flying orbital tourbillon rotates along with the star chart underneath it, which acts as a display of the stars visible above the horizon, as well as the actual indication of sidereal time per se.
Sidereal Time Indication
This is where things get a little hairy, because we think of a day as a fixed entity, consisting of 24 hours. However, our “day” of 24 hours is actually an average of the amount of time it takes for the Sun to pass overhead – the time between two transits of the Sun past a particular point in the sky is a day. This period of time changes from day to day and month to month, thanks to predictable variations in the Earth’s orbit and orbital speed, so what we do for clocks and calendars is take the average; this is the so-called mean – average – solar day. We then squish it down even more to a standard day in different time zones, although mean solar time is different from one location to another. (This is part of the reason that the time zone system was developed – if every town at a different longitude has a different time standard, running a railroad system is both complicated and dangerous).
Sidereal time literally means “star” time; “siderus” is Latin for “star.”
Solar time is determined and defined by the transits of the Sun; sidereal time is defined by the transits of stars and the two, surprisingly enough, are not the same. The transits of the Sun overhead are slightly longer than one full rotation of the Earth around its axis; this is because while the Earth is rotating, it’s also moving along its orbit around the Sun and therefore it has to rotate slightly more than one full rotation for the Sun to pass the same point in the sky.
The fixed stars, on the other hand, are far enough away that they transit across fixed points in the sky more or less at the same instant, no matter where the Earth is in its orbit and therefore, sidereal time is preferred by astronomers, since a given star will return to a given point in the sky at the same time in any sidereal day. The difference between mean solar time is small but significant.
In the Céleste, the orbital tourbillon and the star map on which it rests, rotate counterclockwise once per sidereal day, not once per solar day.
You might notice if you look closely, that there is a fine line on the star chart, which extends from the tourbillon out to a point on the outer Zodiac/Month track that intersects a point in between the Zodiac signs of Virgo and Libra. This point is in Virgo, and it’s the point used to define the beginning of a sidereal day. The point is known, somewhat confusingly, as the Point of Aires, although it’s obviously not in that Zodiac sign.
There is some deep history here. The Point of Aires is the point in the sky where the plane of the ecliptic, or plane in which the planets rotate around the Sun, intersects with the celestial equator; this point, and its opposite in the sky, mark the spring and fall Equinoxes. The Point of Aires used to be in the Zodiac sign of Aires, and when Babylonian astronomers began calculating the Equinoxes and the start of the solar year, it was a natural point to choose as it marked the date when Spring (and Autumn) began.
However, it’s been thousands of years since that convention was established, and the Point Of Aires is no longer in Aires. Thanks to the wobbling of the Earth on its axis – known as the Precession Of The Equnoxes – the point of Aires shifts by about one degree every 72 years. That means that the so-called “Point Of Aires” for the Fall Equinox in September is now in Virgo and the line showing that point, and marking the sidereal day on the Céleste, is now in Virgo as shown on the dial – a little more than 20º.
I have to say, on a purely personal note, I’ve been writing about this watch since it first came out in 2010 and it had never occurred to me to wonder what that little line on the star chart intersecting a point in Virgo might have meant, until I started researching this watch – for what must have been at least the fifth or sixth time – for 1916. That is the great thing about watches, though; every day is a school day.
The Star Chart
As we’ve mentioned, the orbital tourbillon and the star chart on which it sits, rotate together once per sidereal day. There is an oval etched into the crystal; that oval represents the horizon as you would see it if you looked up at the sky and could see which stars were rising and setting as the Earth rotates on its axis. Which stars are visible depends on your latitude. Polaris, the North Star, is currently the brightest star at the apex of the celestial sphere and it appears to be fixed in its position, while the other stars, and the entire sky, rotate around it. (Polaris is represented on the dial of the Céleste by the gold star at the base of the hour and minute hands). This is a major convenience for navigation, since if you want to know your latitude – how many degrees you are above the Equator – you need only measure the altitude of Polaris. (Longitude is a whole ‘nother and much more complicated problem).
Which stars specifically are rising and setting is therefore a question of your latitude; the Céleste shows the sky at 46º North Latitude, which is the latitude of JLC’s factory in the Valée de Joux. It is also conveniently close to the latitude of New York (about 40º North) and Paris (about 48º North; the North Pole is of course, 90º North) so if you are anywhere around New York, Paris, or heaven knows, the JLC factory in Le Sentier, you’re getting a good approximation of the sky overhead. (There is a long tradition of astronomical complications showing the sky over specific locations for well heeled clients; the most notable example is probably the Patek Graves Supercomplication, which showed the night sky over New York).
This particular version of the Céleste is a limited edition of seven pieces and the names of the stars and constellations are in Greek, which, if you’re a student of the history of astronomy and of the ancient Greek language, is an added bonus (I was lucky enough during a period as a stay-at-home dad, to study Greek with a freelance tutor who told me not to ruin a good thing by turning it into a profession).
The Month, Zodiac, And 24 Hour Indication
The hand, or traveling marker I suppose you could call it, which shows these three indications is a demure little pointer in the shape of the Sun, which travels once around the dial once every 24 hours, but which also shifts in position relative to the month and Zodiac sign indications over the course of a year. The gearing must have been interesting to calculate – the Sun marker is used to show the 24 hours of mean solar time, but as it advances against the Zodiac and month scales on the dial, it also shows the position of the Sun in the Zodiac.
As JLC’s Stéphane Belmont pointed out, this means that at a glance, you can see civil time (the hands) 24 hour mean solar time (the Sun marker) and yearly time, so to speak – that is, the tropical year, or the position of the Sun as seen from Earth against the background of stars, all in a single watch.
The Minute Repeater, With Sapphire Gongs And Trebuchet Hammers
JLC has been making repeaters for longer than any of us have been alive, but the company in the 2000s was one of the few firms re-examining every aspect of the complication, and re-thinking every element. The two most distinguishing features of JLC’s research in repeaters are the so-called “trebuchet” hammers, and the sapphire crystal gongs, which in the Céleste are attached directly to the underside of the crystal.
The gongs on most repeaters, are screwed into a steel foot attached to the back of the movement; in pocket watches, the fact that the sound energy had to travel both through the back and front of the watch was not especially a challenge, but in wristwatches, getting the sound energy front and center is a challenge. JLC answered the problem with sapphire gongs, which are attached directly to the underside of the crystal; the result is that sound transmission is unimpeded by the mass of the movement and the case.
The “trebuchet” hammers are named for the medieval siege engine, which used a massive weight to propel projectiles against military targes – the mechanical efficiency of the trebuchet had a lot to do with the abandonment of fixed fortification; with the final nail in the coffin being the invention of artillery. In JLC’s repeaters, the trebuchet hammers are hinged at their center of mass, with recoil springs that both improve the efficiency of energy deliver to the gongs, and prevent the hammers from resting for too long against the gongs and muffling their volume.
A Masterpiece Of Design, And A Masterpiece Of Watchmaking
There are more complicated watches, but there are fewer which capture the romance of complicated watchmaking. The Céleste is unlike anything else in vintage or modern watchmaking – it is not an exercise in tradition exactly (although tradition is deeply part of the watch) nor is it an exercise in disruptive technology. Instead, it is the best of both – a timepiece deeply connected to the most ancient traditions of observational astronomy, going back thousands of years to ancient Greece and Babylon, but which also incorporates some of the most cutting edge innovations in horology.
It is in fact, if you are a lover of complicated watchmaking, as good as it gets – a miniature representation of the universe as see from Planet Earth.