Vacheron Constantin Celestia Astronomical Grand Complication Homage to Ptolemy and Copernicus

Vacheron Constantin is marking its 270th anniversary with a new series of watches from its Les Cabinotiers department, a collection titled 'La Quête'. This series pays tribute to the long-standing human fascination with astronomy, a field Vacheron Constantin has explored mechanically for centuries. At the forefront of this new collection are two single-piece editions, the Les Cabinotiers Celestia Astronomical Grand Complication watches. These two models, one an homage to Ptolemy and the other to Copernicus, use an identical, hyper-complex movement but are encased in distinct metals, each hand-engraved to represent two conflicting and era-defining views of the cosmos.

The philosophical divide between these two timepieces is central to their creation. They represent the monumental shift in human understanding from geocentrism to heliocentrism. The first model honors Claudius Ptolemy, the 2nd-century astronomer from Alexandria. His model of the universe was the standard for 1,500 years, placing a motionless Earth at the center of everything, with the planets and stars revolving around it in harmonious, perfect circles. This was the accepted truth for millennia, a system that defined science, philosophy, and religion.



The second watch pays tribute to Nicolaus Copernicus, the Polish astronomer who, many centuries later, triggered a revolution. He proposed a heliocentric model, identifying the Sun as the true center of our system. This was not a new idea—it had been suggested by Aristarchus of Samos in the 3rd century BC—but Copernicus provided the mathematical framework that eventually overturned Ptolemy's 1,500-year-old doctrine. This shift paved the way for modern astronomy, and Vacheron Constantin has chosen to embody these two worldviews in metal, one representing an ancient, Earth-focused universe and the other a modern, Sun-focused one.

At the heart of both watches is the Manufacture Calibre 3600. This is not a new movement, but its re-application here is fitting. First presented in 2017 in the original Les Cabinotiers Celestia watch, it was the result of five intense years of development. It is a manually wound, double-sided calibre that incorporates an incredible 23 astronomical complications. The sheer density of its engineering is staggering, with 514 components and 64 jewels all working in concert. It won the Mechanical Exception award at the Grand Prix d'Horlogerie de Genève in 2017, and its inclusion here provides the technical foundation for the artistic expression of the cases.

What makes the Calibre 3600 such a standout is its feat of miniaturization. Grand complication movements are, by nature, thick and complex. This one, however, manages to integrate 23 functions, including three distinct time-telling gear trains, into a movement that is only 8.7 mm thick. The entire case, front and back crystals included, is only 13.91 mm thick. This thinness is remarkable given the sheer volume of information the watch displays. The movement is certified with the Hallmark of Geneva, indicating a high standard of finishing on all 514 components, even those that will never be seen by the owner.

Powering this complex machine requires significant energy. The Calibre 3600 achieves a massive three-week power reserve. This is accomplished not with one large mainspring, but with six barrels mounted in series. The movement runs at a steady 2.5 Hz, or 18,000 vibrations per hour. On the reverse side of the watch, visible through the sapphire crystal, is the one-minute tourbillon. Its cage is shaped into Vacheron Constantin's emblem, the Maltese cross. The brand's watchmakers strategically placed the tourbillon on the back to free up valuable space on the front dial for the dense astronomical displays.



The primary function of the Celestia is the display of three different times, each driven by its own dedicated gear train. The front dial displays both civil time and solar time. Civil time is the standard 24-hour mean time we live by. Solar time, or true time, is based on the actual position of the sun in the sky. These two times are rarely the same. Because of the Earth's elliptical orbit and the 24-degree tilt of its axis, the time between two passages of the sun at its zenith—a true solar day—varies slightly. This difference between the solar day and the 24-hour civil day is known as the "equation of time."

This variation can range from solar time being 16 minutes behind civil time to 14 minutes ahead, and they only align perfectly four times per year at the solstices and equinoxes. The Calibre 3600 mechanically calculates and displays this differential using a "running equation of time." This is not a subdial you have to mentally add or subtract. Instead, a second, coaxial minute hand, tipped with a small sun, moves independently of the main minute hand. This sun-tipped hand automatically runs ahead of or behind the civil minute hand, allowing for an instantaneous reading of both true solar time and mean civil time.

The third time, sidereal time, is found on the back of the watch. A sidereal day is time measured relative to the fixed stars rather than the Sun. As the Earth orbits the Sun, it takes slightly less time to complete a 360-degree rotation relative to a distant star. A sidereal day is, therefore, approximately four minutes shorter than a calendar day, lasting exactly 23 hours, 56 minutes, and 4 seconds. The sidereal time scale is marked on the edge of a mobile disc on the caseback, which visibly rotates four minutes faster than the civil time display each day.

The front dial of the "Homage to Ptolemy" model is crafted from 18K white gold with a fine, grained texture. The hands and applied hour-markers are also 18K white gold. The layout is dense with information, yet remains legible. At 1 o'clock, two windows indicate the day and month. These are part of a perpetual calendar, which also includes a date display on a subdial at 3 o'clock, indicated by a serpentine hand. A small circular aperture just above that subdial displays the leap year, a system mechanically programmed to be accurate until the year 2100.



At 9 o'clock, a precision moon phase indicator is displayed. This complication is accurate to one day's error every 122 years. It is built from two superimposed discs: a lower disc shaded to show day and night, and a transparent upper disc bearing a laser-engraved representation of the moon. The periphery of this subdial allows the wearer to read the age of the moon, or the number of days that have passed since the last new moon.

The lower half of the dial is dedicated to complications directly related to the sun's position. Two slender hands on graduated scales indicate the sunrise and sunset times for the owner's location. Positioned between these two scales is a vertical gauge that visually represents the length of the day and night, expanding and contracting with the seasons.

At 4 o'clock, a rotating annual disc shows the astronomical signs of the zodiac, the current season, and the dates of the solstices and equinoxes. Completing the suite of complications at 11 o'clock is a mareoscope, or tide gauge. This is an exceptionally rare function in watchmaking. It displays the current tidal level, and, in a fascinating three-dimensional cutout, shows the alignment of the Earth, Moon, and Sun. This alignment is the mechanism that governs tidal amplitude, with the highest "spring" tides occurring when all three bodies are aligned during a new or full moon.

The "Homage to Copernicus" model features the exact same layout and set of complications, but its execution is in 18K 5N pink gold. The dial has the same grained finish but in a warm rose-gold tone. The hands and applied markers are also crafted from 18K 5N pink gold. This warm palette is contrasted by the deep, dark blue of the Mississippiensis alligator strap, creating a different visual presence from its white gold counterpart. The intricate complications, like the blued hands for the sunrise/sunset indicators and the blue of the moon phase disc, stand out sharply against the pink gold background.

The reverse side of both watches is dedicated to the celestial map, which also indicates sidereal time. This display is composed of two superimposed sapphire discs. The upper disc is fixed and features the constellations of the Northern Hemisphere, as well as indications for the Milky Way. The lower disc is mobile, rotating at the sidereal rate. A yellow triangular pointer indicates the current date against the rotating disc.



On this mobile disc is an off-center blue ellipse that serves as the background "sky." This ellipse shows which of the constellations on the upper disc are visible from a given location on Earth in real-time. The display also includes a white elliptical line to indicate the celestial equator (the projection of Earth's equator into space) and a red elliptical line to indicate the ecliptic (the plane of Earth's orbit around the Sun). The entire caseback is a constantly changing, miniature planetarium. The outer edge of this display is used as a peripheral power reserve indicator for the three-week capacity.

The true artistry that separates these two "pièce unique" models is the extensive hand-engraving on the cases. Each watch took a single master engraver 240 hours to complete, using the champlevé technique. This involves hollowing out the metal to create a recessed background, which is then finely hand-chased to create a "sandblasted" texture. The original, raised surfaces are then polished, creating a striking contrast between the textured background and the high-gloss lines of the design.

The 18K white gold "Ptolemy" watch features a geocentric universe engraved onto its case, lugs, and bezel. The planets are shown in their orbits, all revolving around the Earth, which is represented as a domed planisphere on the crown. The greatest challenge for the engraver was maintaining the symmetry and regularity of the planetary ellipses as they travel from the caseband, over the lugs, and onto the bezel. Any break in the lines would have ruined the effect. The planets themselves are subtly domed and textured to appear cosmic, while the tiny continents on the Earth-crown are hand-polished.

The 18K 5N pink gold "Copernicus" watch illustrates the heliocentric system. Here, the crown is the Sun, with polished rays of light engraved radiating outwards across the case and lugs. The planets are shown moving in their respective orbits around this central Sun. This design presented its own unique challenge: the geometric centers of the planetary orbits were located on the left side of the case, outside the physical frame of the watch. The engraver had to create a special compass-like tool to draw these large circular arcs perfectly on the case's curved surfaces. The planets are again engraved in relief with a domed effect, polished to stand out from the chased background.



Both watches are presented in a 45 mm case that is 13.91 mm thick. They are rated for water resistance to 3 bar, or approximately 30 meters. Each is paired with a dark blue Mississippiensis alligator leather strap, which features an alligator leather inner shell and is hand-stitched with a saddle-finish. The straps are secured with a hand-engraved folding clasp in 18K white or 18K 5N pink gold, matching their respective cases.

As single-piece editions from the Les Cabinotiers department, these watches are the definition of exclusivity. The caseback of each is engraved with "Pièce unique" and "Les Cabinotiers" to confirm its status. Vacheron Constantin does not provide public pricing for creations at this level. They are available only by application, representing a summit of mechanical complexity and artisanal craft dedicated to the human quest to understand the cosmos.

Les Cabinotiers Celestia Astronomical Grand Complication Homage to Ptolemy

Case: Hand-engraved 18K white gold, 45 mm diameter, 13.91 mm thick. Double-sided case. Water resistance tested at a pressure of 3 bar (approximately 30 metres).

Movement: Calibre 3600, mechanical manual winding. 36 mm diameter, 8.7 mm thick. 514 components, 64 jewels. 2.5 Hz (18'000 vibrations/hour). Approximately 3 weeks power reserve via six barrels. One-minute tourbillon.

Dial: Grained 18K white gold. 18K white gold appliques and hands. Double-sided display with 23 astronomical complications including civil, solar, and sidereal time, perpetual calendar, precision moon phase, running equation of time, sunrise/sunset, tide level indicator, and celestial chart.

Strap: Dark blue Mississippiensis alligator leather with alligator leather inner shell, hand-stitched, saddle-finish, large square scales. Hand-engraved 18K white gold folding clasp.

Price: Upon Request

Reference Number: 97A0C/000G-304C

Notes: Single piece edition ("Pièce unique"). Hallmark of Geneva certified. Case engraving illustrates Ptolemy's geocentric system using champlevé technique, representing 240 hours of work.



Les Cabinotiers Celestia Astronomical Grand Complication Homage to Copernicus

Case: Hand-engraved 18K 5N pink gold, 45 mm diameter, 13.91 mm thick. Double-sided case. Water resistance tested at a pressure of 3 bar (approximately 30 metres).

Movement: Calibre 3600, mechanical manual winding. 36 mm diameter, 8.7 mm thick. 514 components, 64 jewels. 2.5 Hz (18'000 vibrations/hour). Approximately 3 weeks power reserve via six barrels. One-minute tourbillon.

Dial: Grained 18K 5N pink gold. 18K 5N pink gold appliques and hands. Double-sided display with 23 astronomical complications including civil, solar, and sidereal time, perpetual calendar, precision moon phase, running equation of time, sunrise/sunset, tide level indicator, and celestial chart.

Strap: Dark blue Mississippiensis alligator leather with alligator leather inner shell, hand-stitched, saddle-finish, large square scales. Hand-engraved 18K 5N pink gold folding clasp.

Price: Upon Request

Reference Number: 97A0C/000R-290C

Notes: Single piece edition ("Pièce unique"). Hallmark of Geneva certified. Case engraving illustrates Copernicus' heliocentric system using champlevé technique, representing 240 hours of work.