In 2016, BOVET 1822 presented the Récital 18 Shooting Star®, which made headlines for its innovative time display. The Récital 20 Astérium® seamlessly continues the tradition set by its illustrious predecessor, reprising the characteristic shaped case to present an unprecedented mechanical display that showcases the volumes and decoration of the timepiece.
Time is defined by the position of the stars in the sky. Based on this undeniable fact, the night sky was chosen to play the ‘starring’ role in this new exceptional timepiece. Faithful to the underlying principles governing complication development at BOVET 1822, this sky map was designed to be functional, precise and intuitive all at once. With this in mind, the BOVET 1822 technicians opted to map out the stars and constellations visible from the Earth on a dome of translucent blue sapphire, on which they are laser-engraved before being coated in Super-LumiNova® to create a dazzling true-to life sky. To ensure utmost realism, the highest stars in the sky are depicted at the top of the dome while the lowest stars nearer the horizon appear on the periphery of the display aperture. Yet, this unrivalled exactitude in time display would count for little had Pascal Raffy and his artisans not applied the same rigor to the mechanical precision of the timepiece. To this end, they devised a sidereal calendar.
The duration of a complete Earthly orbit (known as a sidereal year) is 365 days, 6 hours, 9 minutes and 9.77 seconds, or an unchanging 365.25 days. For obvious reasons, the Gregorian calendar was obliged to round down the number of days in a year to 365 and to compensate for the remaining hours by adding an extra day every four years, giving us our leap years. While the Gregorian calendar is perfect for governing our everyday lives, it differs by 0.25 days per year from sidereal reality before resynchronizing every four years. The calendars usually employed in watchmaking – perpetual or otherwise – are all based on the Gregorian calendar, and the use of such a mechanism to drive a night sky results in a significant cumulative error when reading off the time.
The night sky and the collection of sidereal indications on the Astérium® are thus governed by an annual calendar calculated on a 365.25-day cycle to reflect the real duration of one full terrestrial orbit. Thanks to this combination of display and horological exactitude, the instantaneous position of the stars in the sky is thus displayed with unrivalled precision.
While complex ingenuity went into developing the Astérium®, its mechanism and winding device are designed to be simple, intuitive and reliable, as can be seen by merely turning the timepiece over and looking through the transparent sapphire crystal covering the entire movement. It features a host of graduations linked to the astronomic indications through which a single central hand travels. This hand is driven directly by the annual calendar, and therefore performs a complete rotation once every 365.25 days.
An annual calendar (dates and months) is graduated on the case-back bezel and serves to precisely regulate the night sky. Rapidly setting the time with the crown in the intermediate position disconnects the hours and minutes hands, and enables both the position of the night sky and thus all sidereal information to be adjusted both quickly and easily. To do this, the wearer simply moves the central hand forward until it reflects the correct date before adjusting the time with the crown in its middle position. This operation takes far less time than adjusting a perpetual calendar would, and does not require a corrector. The same hand also travels along a graduation indicating the signs of the zodiac, symbolized by the constellations in front of which the sun appears throughout the year – hence the delicately hand-engraved sun that is riveted to the part of the hand that passes over this section. The seasons are also indicated further inside the timepiece, as are the solstices and equinoxes.
Returning to the front of the timepiece unveils some new additional indications. The lower left- and right-hand sections of the night sky overlook two double hemispheric indicators, while on the left, an hemispheric precision moon phase lingers above the equation of time indicator.
The duration of the true solar day – which corresponds to the exact interval of time between two passages of the sun at its zenith at an identical given point – varies throughout the year. In fact, the Earth takes exactly and consistently 23 hours and 56 minutes to rotate 360° on its own axis. But depending on the Earth’s position in its orbital ellipse, the sun will appear either earlier or later at the zenith at this identical point relative to the average 24-hour solar day.
Depending on the Earth’s position in its orbital ellipse, two periods in which the sun is late will therefore be interrupted by two periods in which the sun is early in relation to our average solar day. On the lower right-hand section of the night sky is a double hemispheric indicator positioned symmetrically opposite the moon phase and equation of time displays. This shows the power reserve and its ten days of autonomy via an internal dome that evolves beneath a fixed hour-marker. The retrograde minutes hand is positioned above it and displayed on the periphery.
In accordance with astral time, the hours pass concentrically across the night sky on a 24-hour dial that is positioned beneath the night sky and visible through the transparent sapphire. To ensure intuitive use and optimal legibility, the hours hand has been designed to execute three functions simultaneously: it indicates the time, points to the north to facilitate map-reading, and carries the elliptical window characteristic of the night sky. Following the curves of the sapphire dome, this triple hand alone symbolizes the Manufacture’s truly diverse range of skills. From its development and its many delicate hand-crafted decorative flourishes to the hi-tech virtuosity that went into its machining, the creation of this hand is a concentration of technical feats all masterfully realized by the BOVET 1822 artisans. Finally, the seconds hand is driven by the patented double face flying tourbillon.
Despite its complexity, setting this timepiece is as quick and easy as for a timepiece with a simple calendar mechanism. The same applies when determining the position of the stars in the sky. To do this, simply point the arrow of the sky map hand northwards. The ellipse opened by this sky map hand outlines the part of the sky that is visible from the wearer’s position at the moment of observation, assuming that the observer is positioned in the center of the elliptical window and enjoys a 360° view.
Whatever the field, the very essence of art lies in an artist’s ability to simplify something that is inherently complex. In this sense, BOVET 1822 watchmakers have demonstrated true artistry in the Astérium®. Once again, by building on their exceptional experience and infusing their work with cutting-edge research, they have driven back the boundaries of perfection.
A single barrel regulates the energy of the timepiece and maintains the oscillations of the balance wheel at 18,000 vph for an autonomy of 10 days. This power reserve remains entirely unaffected by the many indications and the technical intricacy of their displays. The moon phase and power reserve domes, as well as the sapphire night sky dome, are adjusted by patented variable micrometric bearing-blocks composed of ruby runners. This ingenious mechanism is extremely energy-efficient and has already proven its worth in the movement of the Récital 18 Shooting Star®.
The patented double face tourbillon which regulates the Récital 20 Astérium® is equipped with a variable inertia balance wheel. The six collets distributed along the surface of the felly help refine dynamic adjustment for even better chronometry. And once completed and adjusted, each balance wheel is carefully selected and paired with the balance-spring with which it will form the best possible pairing. Through their perfectly mastered manufacture of traditional balance wheel and balance-springs, BOVET 1822 watchmakers continue to constantly redefine the boundaries of isochronism and chronometry. The three arches on the bridge of the titanium carriage – all rounded-off and polished by hand – expertly protect the heart of the timepiece. Their design is suggestive of a Gothic vault, of a cathedral without a roof open to the universal magic of stellar mechanics.
The layout of this side of the movement follows the inclination of the bezel that characterizes this case design. The tourbillon carriage wheel and the seconds hour-marker screwed onto it are on the same level as the plate. Two levels of bridges then fan out from the center of the tourbillon carriage. The upper bridges are screwed to the bottom level by hand-polished pillars, which ensure harmonious volumes and draw the gaze. Finally, the three domes overlook the entire movement, offering a panoramic view of time and space that is both poetic and original.
The decor of the movement matches its ingenuity and innovative structure. For maximum elegance, the Manufacture’s engravers have chosen highly subtle and delicate chiseling to decorate the surface of the bridges and plate. The surface demonstrates all the finesse of graining and all the brilliance of a ‘bris de verre’ motif. This contrasts perfectly with the framework of polished angles tracing the contours of the bridges, and guarantees a clear reading of both the night sky and the sapphire rear dial, all the while affording the admiring observer a clear view of the movement’s architecture and decoration.
Only sixty Astérium® movements will be manufactured across all versions, including requests for unique pieces. Collectors can choose from red gold, white gold or platinum cases, which can be customized by the Manufacture’s artisans in a tradition that has distinguished BOVET 1822 for 195 years.
Model: Récital 20 Astérium®
10-Day Flying Tourbillon Night Sky Annual Calendar with Astronomical Functions
Thickness (With Glasses): 18.3mm
Thickness (Without Glasses): 7.5-14.3mm
Gold Weight: 73.49gr (red gold) / 76.90gr white gold)
Case Material: 18K red or white gold or platinum 950/1000
Water Resistance: 30m
Display mechanism with radial guidance
Double face tourbillon
Frequency: 18’000 vph
Power reserve: 10 days
Hours (24h), retrograde minutes, seconds on tourbillon, annual calendar, night sky, equation of time, precision moon phase indicator, season, solstice and equinox indicator, astrological zodiac indicator and power reserve indicator
Limited Edition of 60 movements
Full skin alligator
Buckle: 18K red or white gold ardillon
5 years Warranty