This year is quite the anniversary for Vacheron Constantin, with the brand turning 270 years old. To mark the occasion appropriately, the Geneva-based manufacture created the mighty Les Cabinotiers Solaria Ultra Grand Complication – La Première, the culmination of eight years of development.

Now the most complicated wristwatch ever, this unique wristwatch boasts 41 complications on two faces, encompassing five rare functions as well as a world first – a celestial object tracker. All of that is contained in a surprisingly compact, but still large, case. (A detailed list of the complications is available in the addendum below.)

Initial thoughts

Timepieces of such complexity reach beyond the realm of horology and can be regarded as engineering marvels. In a sense the Solaria is not unexpected since VC has a long history of making ultra-complications – “The Berkley” pocket watch was just unveiled a year ago – but the Solaria is one of the most fascinating watches in recent memory.

The numbers behind the Solaria are impressive. Beyond the 41 functions, the watch is powered by the cal. 3655 that’s made up of 1521 pieces and the subject of 13 patents. The watch took eight years to develop and construct, which is impressive for a single timepiece.

Surely VC will trickle down some of the developments related to cal. 3655 and install them in simpler timepieces, but condensing 41 complications into a wristwatch no thicker than 15 mm is an engineering feat that cannot be understated.

Something that might go unnoticed amidst all the complexity is the silicon balance wheel, which is a first for VC and also unusual in such a complicated watch. The implications of this material are interesting; will it be adopted over a wider range of models?

If there is a shortcoming in the Solaria, it is a trait that is common to all such mega complications: the impractically complicated appearance that is a challenge to process.

There is so much information condensed in the overlapping displays that the dials do look cluttered. Legibility is certainly not its strength, but arguably such visual complexity is intrinsic to a watch of this calibre. Given the extraordinary nature of the Solaria, some aesthetic compromises can be overlooked. 

Forty-one complications

The Solaria boasts 41 complications, with five of them being “rare” according to VC – an accurate enough claim. Four of these are linked to the Sun and its position, while the fifth is a complete world first.

The Solaria displays the position, height, culmination and declination of the Sun. These four complications are linked to the apparent path of the Sun, as observed from a given position on Earth. 

The position of the Sun is indicated at the periphery of the dial, on a rotating sapphire ring. When oriented in accordance with the cardinal points, the watch reliably displays the Sun’s position in the sky, along with the sunrise and sunset times.

The height of the Sun indication expressed in degrees (between 20° and 68°) displays the elevation of the Sun above the horizon line.  

The culmination of the Sun is displayed in the same six o’clock large sub dial as the height and declination. The culmination of the Sun (also known as solar noon) is when the star reaches the highest point in its daily trajectory. This indication is somewhat subjective, since it is dependent on the observer’s longitude. 

Lastly, the declination of the Sun represents the angle formed by the Earth’s equatorial plane and an imaginary segment joining the Sun and Earth. It increases from −23.5° in winter solstice to +23.5° in summer solstice, having a value of zero at equinoxes. 

This indication is displayed at six o’clock, integrated with the others. The same sub-dial also houses a running equation of time indicator and a counter displaying the 13 constellations of the zodiac (including Ophiuchus), along with the seasons, solstices and equinoxes. These complications together are already more advanced than a full perpetual calendar. 

A world-first astronomical complication

Turning the watch around, and another dial displaying additional complications is revealed.  The fifth “rare” complication — a world first — is linked to the rattrapante chronograph on the reverse face.

This complication is a celestial object tracker. Twin superimposed tinted-sapphire disks form a star chart that revolves in real time. This works together with a split-seconds chronograph to calculate the time required for a specific constellation to appear in the wearer’s field of vision. 

To use the celestial body tracker complication, the wearer must choose a star on the celestial chart and start the chronograph.

Stop the split chronograph hand once it aligns with a green reference marker, but allow the other seconds hand to continue until it reaches the current position of the chosen star, then stop it as well. 

The green triangle on the small central counter indicates the number of hours remaining until the star will become visible. The complication’s presentation may be a little difficult to fully understand, but the purpose is surprising and admittedly novel.

The split-seconds chronograph can be used just for conventional elapsed timing as well, as the chronograph also includes a 60-minute counter in disc form.

One of the many patents in the movement is linked to the split function, which comes with an isolateur that assures there is no additional friction to the split-seconds shafts when the chronograph is engaged. 

Westminster chime

Accounting for seven out of the 13 patents in the Solaria, the Westminster carillon minute repeater is integrated into the base movement. This is no small feat, considering additional modules for the astronomical complications also needed to be taken into account. 

The carillon repeater requires four hammers and four gongs for the complex musical sequence. Because the movement is so dense, classic chiming systems were not suitable, since the sound was dampened by the sheer amount of tightly packed metal pieces.

As such, the gongs are shaped with a rectangular section and are directly attached to the middle case, which promises to increase the resonance of the chiming. 

The hammers also feature a proprietary design. They are compact in shape and made from steel, but with added 18K gold weights in order to increase their moment of inertia. 

More indications…

Apart from the sounding and astronomical complications, the Solaria also features classic indications and functions that traditionally define high complication pieces. 

The Solaria includes a complete perpetual calendar, which displays the correct date, including the year in a four-digit format. There is also a moon phase indication, which is disappointingly only accurate for the industry norm of one day in 122 years, after which it requires manual adjustment. 

Additionally, the Solaria has both a 24-hour time display and a world time indication calibrated to standard winter time. This means that the already complex timepiece can simultaneously track three different timezones (including the local time shown by the central hands).

With “plug and play”

While the chiming mechanism is integrated into the base movement along with the going train and tourbillon regulator, the astronomical complications form the upper layers of the cal. 3655. The innovative “plug and play” device is a clever way of integrating the astronomical complications. 

In order to ease any future servicing work, the astronomical module is a single functional unit, assembled and adjusted separately from the rest of the movement. A clever indexing system assures the module is positioned correctly, allowing it to be installed and then immediately be driven by the base movement. 

This type of connection will undoubtedly be used by VC in the future for simpler movements with comparable modular constructions, like a perpetual calendar for example. 

Addendum: The 41 complications

Time functions

1.     Day and night indication for reference city
2.     Second time zone hours and minutes (on 24-hour display )
3.     World time indication for 24 cities
4.     Second time zone day and night indication
5.     3Hz tourbillon with silicon balance wheel
6.     Civil time display module coupled to the base movement

Perpetual Calendar

7.     Perpetual calendar
8.     Days of the week
9.     Months
10.   Gregorian retrograde date
11.    Four-digit year indication
12.    Leap-year indication
13.    Indication for the number of the week within the year (ISO 8601 calendar)
14.    Number of the day of the week (ISO 8601 calendar)

Lunar indications

15.    Astronomical Moon phases and age of the Moon
16.    Tide level indicator
17.    Spring and neap tides indication

Astronomical indications

18.    Indication of seasons, equinoxes & solstices
19.    Position of the Sun20Sunrise time (according to the city of reference)
21.    Sunset time (according to the city of reference)
22.    Duration of the day (according to the city of reference)
23.    Equation of time on tropical (solar) gear
24.    Culmination time of the Sun (according to the city of reference)
25.    Height of the Sun above the horizon (according to the city of reference)
26.    Declination of the Sun, Three-dimensional Earth showing the latitude of the Sun in the Northern/Southern hemisphere
27.    Sidereal hours
28.    Sidereal minutes
29.    Astronomical zodiac signs
30.    Sky chart (according to the city of reference)
31.    Temporal tracking of celestial objects

Chiming complications

32.    Minute repeater
33.    Westminster carillon chime (4 hammers & 4 gongs)
34.    Choice of hour-only or full chime
35.    Crown locking system during the chiming
36.    Double-stop hammer system to limit rebound and optimise transmission of energy

Split-seconds chronograph

37.    Chronograph (1 column wheel)
38.    60-minute counter
39.    Split-seconds chronograph (1 column wheel)
40.    Isolator system for the split-seconds chronograph

Additional feature

41.    Power-reserve indication (outer disc at 190°)

Key facts and price

Vacheron Constantin Les Cabinotiers Solaria Ultra Grand Complication – La Première
Ref. 9600C/000G-231C

Diameter: 45 mm
Height: 14.99 mm
Material: 18k white gold
Crystal: Sapphire
Water resistance: Moisture protected

Movement: Cal. 3655
Functions: Grande complication with 41 functions, including a celestial object tracker
Winding: Manual wind
Frequency: 21,600 vibrations per hour (3 Hz)
Power reserve: 72 hours

Limited edition: Single-piece edition as shown
Availability: Made to order with each example being unique
Price: On request

For more information, visit Vacheron-constantin.com.