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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11The 2017 Les Cabinotiers Celestia Astronomical Grand Complication 3600 is a hand-wound watch built around calibre 3600, a 514-part integrated movement that Vacheron Constantin describes as carrying 23 essentially astronomical complications. It shows civil, solar and sidereal time, each driven by its own gear train, and its indications are spread across the front and back of the dial. The short answer to “what does it show” is far more than the time of day, presented as a set of interlocking astronomical cycles rather than a list of unrelated functions.
This article is built from Vacheron Constantin’s 2017 technical description of the watch and from Hodinkee’s 2017 coverage, with Hodinkee’s 2025 coverage used for the later Homage pieces. It does not report time spent wearing the watch, so where a detail comes from a source, that source is named.
Which Celestia this article covers
Vacheron Constantin has used the Celestia name on more than one watch, so the reference matters. This article covers only the original 2017 Les Cabinotiers piece, which Hodinkee identifies as reference 9720C/00G-B281 in 18k white gold. The original is described as a unique piece.
In 2025, as part of its La Quête series for the brand’s 270th anniversary, Vacheron Constantin introduced two further unique Celestia watches, Homage to Ptolemy and Homage to Copernicus. They retain calibre 3600 but have their own cases and engraved cosmological concepts. They are treated in their own section below and should not be read back into the original’s specifications.
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#1 Best Overall
- Metal Type: White Gold
- Imported
- Excellent condition - Minimal signs of wear consistent with pre-owned use. This item is pre-owned and may show light signs of wear. Please refer to the condition and photos. All of our products are authenticated and certified by our team of luxury experts.
- Wrist Size: 6.50"
- Case Size: 21mm
What unifies the complications
The Celestia is organised less as a count of functions than as a set of cycles. Each complication tracks a different way people have measured time, and the watch brings them into one hand-wound movement. The cycles Vacheron Constantin’s presentation and coverage point to are:
- Sidereal time, the day measured against the fixed stars.
- Mean solar time, the average solar day that clocks are built on.
- The tropical year, the cycle of the seasons that drives equinoxes and solstices.
- The synodic month, the roughly 29.5-day cycle of the moon’s phases.
- The lunar day, the interval between successive moonrises, which is longer than a solar day.
- The civil year, the calendar that daily life runs on, including leap years.
Seen this way, the question is not how many complications the watch has but how many of these cycles one movement can keep track of at the same time.
Calibre 3600 specifications
The movement figures below come from Vacheron Constantin’s 2017 description unless marked otherwise.
| Attribute | Value | Source |
|---|---|---|
| Calibre | 3600, integrated, hand-wound | Vacheron Constantin 2017; hand-winding as reported in Hodinkee’s 2017 coverage |
| Components | 514 parts | Vacheron Constantin, 2017 |
| Movement thickness | 8.7 mm | Vacheron Constantin, 2017 |
| Movement diameter | 36 mm | 2017 coverage of the watch |
| Barrels | Six | Vacheron Constantin, 2017 |
| Autonomy | Three weeks, which the brand attributes to the six barrels | Vacheron Constantin, 2017; figure as stated at launch, not independently tested |
| Complications | 23, described as essentially astronomical | Vacheron Constantin, 2017 |
| Time modes | Civil, solar and sidereal, each on a separate gear train | Vacheron Constantin, 2017 |
Three time modes on one movement
Vacheron Constantin states that the watch reads time in three modes, each driven by its own gear train. Each mode answers a different question, which is why the brand keeps them separate.
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- Size: 20mm
- Clasp style: folding buckle
- Material: 316L Stainless Steel
- What's in the box: 1 buckle, 1 tool, 1 pair of unprocessed ears
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Civil time
Civil time is the clock time used in ordinary life, set by time zones and the conventional calendar. It is the reading most people mean when they say the time, and it is the one the rest of the watch is built around.
Solar time
Solar time is based on the sun. Apparent solar time is what a sundial shows, and mean solar time is the evenly paced average that clocks follow. The difference between the two is the equation of time, which the front dial indicates with a dedicated hand (see the dial section below). Over the course of a year that difference can reach roughly 16 minutes.
Sidereal time
Sidereal time is measured against the fixed stars. A sidereal day is about four minutes shorter than a solar day, roughly 23 hours and 56 minutes, which is why the same star rises a little earlier each night. The reverse of the watch carries a star chart keyed to sidereal time, which is where this mode becomes visible.
Front dial indications
Alongside conventional hours and minutes, Hodinkee’s 2017 coverage describes the following on the front of the watch:
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- Band lug width and Length: The strap width is 25mm*8mm, and the strap length is 70mm+110mm
- Compatible Modles: Perfect Compatible for Vacheron Constantin Overseas Watch Strap
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- A moon-phase display.
- Sunrise and sunset indications.
- Length of day and length of night.
- A zodiac-sector display.
- Equinoxes and solstices.
- A “marchant” hand for the equation of time, as Hodinkee names it.
- An instantaneous perpetual calendar with a leap-year indication.
- A Mareoscope, which combines the lunar phase with a tide chart.
Reverse dial: star chart and power reserve
The reverse carries a planispheric star chart, a rotating map of the sky set for the current sidereal time. According to Hodinkee’s 2017 introduction, the chart shows the stars above the horizon, the position of the Milky Way, sidereal time, the celestial equator and the ecliptic. The same introduction says the chart uses two sapphire disks. The reverse also carries the power-reserve indication.
Case and finish of the original
| Attribute | Value | Source |
|---|---|---|
| Reference | 9720C/00G-B281 | Hodinkee, 2017 |
| Case metal | 18k white gold | Hodinkee, 2017 |
| Case dimensions | 45 mm diameter by 13.6 mm thick | Hodinkee, 2017 |
| Dial | Slate-coloured | Hodinkee, 2017 |
| Hallmark | Geneva Hallmark | Hodinkee, 2017 |
| Water resistance | Three bar | Hodinkee, 2017 |
A three-bar rating is a splash-resistance figure. It indicates protection from water spray and rain, not suitability for swimming or diving.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.The 2025 Homage pieces compared
Homage to Ptolemy and Homage to Copernicus share calibre 3600 and the 23-complication count with the original, but they differ in the points below. The 2025 figures are as reported by Hodinkee’s 2025 coverage and by Vacheron Constantin’s La Quête page.
| Attribute | 2017 original | Homage to Ptolemy (2025) | Homage to Copernicus (2025) |
|---|---|---|---|
| Release context | 2017 Les Cabinotiers unique piece | 2025 La Quête series, 270th-anniversary | 2025 La Quête series, 270th-anniversary |
| Calibre | 3600 | 3600 | 3600 |
| Complications | 23, essentially astronomical | 23 astronomical | 23 astronomical |
| Case metal | 18k white gold | 18k rose or white gold; the cited coverage does not state which metal goes with which model | 18k rose or white gold; the cited coverage does not state which metal goes with which model |
| Diameter | 45 mm | 45 mm | 45 mm |
| Thickness | 13.6 mm (2017 coverage) | 13.91 mm (2025 coverage) | 13.91 mm (2025 coverage) |
| Cosmological concept | Astronomical presentation of cycles | Geocentric engraving | Heliocentric engraving |
The thickness figures come from different coverage years and should be read as reported, not as a like-for-like measurement of the same case. The engravings are the main reason to tell the 2025 pieces apart: Ptolemy’s is geocentric, with the Earth at the centre, and Copernicus’s is heliocentric, with the sun at the centre.
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Availability, ownership and price
The sources establish the original as a unique piece. They do not establish who owns it now, whether it is currently offered for sale, or what it would cost today. Older price references are not reliable evidence of a present price or resale value, so they should not be used to judge the watch’s market.
Anyone interested in a one-of-a-kind Celestia-style commission can contact Vacheron Constantin directly through its Les Cabinotiers bespoke service, which invites enquiries and appointments. The cited material does not describe what a commission would cost or how long it would take.
Who the Celestia makes sense for
The Celestia is best understood as a demonstration of how much astronomical information a single hand-wound movement can carry, and as an object for collectors who care about the idea of cycles as much as the dial layout. Because the original is documented as a unique piece, the practical question is not which model to pick but whether the watch, or a commission in the same spirit, is reachable at all.
Buyers looking for a catalogue watch with similar functions should compare the 2025 Homage pieces only on their own terms, since they are separate unique creations with different cases and concepts.
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The Bottom Line
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Treat the 2017 Celestia as a documented one-off: a calibre 3600 movement with 23 essentially astronomical complications, three time modes and a sky-facing reverse. Check the 2017 and 2025 figures against their own sources, and confirm current availability with Vacheron Constantin before assuming the watch can be bought.
Quick Recap
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
