Back in the 18th century, watchmakers were concerned with making timepieces that would not only measure average solar time – the one we apply in our everyday lives – but also sidereal time, which we use for the celestial map in the heavens, traditionally for navigation purposes.
The Récital 20 Astérium (the sky seen from the Earth) is Bovet’s poetic and precise embodiment of the same idea for a watch. It contains a host of astronomical complications, all housed in their trademarked writing slope case, in a combination of 18kt white and red gold.
What makes the Astérium visually stunning is the spectacular movement on full display. Front and centre is the laser-engraved night sky map of the stars and constellations, which are filled with Super-LumiNova, on a dome of translucent blue quartz. The hour hand has three functions: it indicates the time, points to the north to facilitate map reading, and carries the elliptical window for the night sky.
To determine the position of the stars, the wearer only has to point the arrow in the sky map northwards. Quick and easy.
To the right of the night sky is a retrograde average solar time minute counter. The 10-day power reserve is shown next to the minute display. On the opposite side, we find a moon phase alongside an equation of time indicator, which marks the difference between solar or sidereal time (as measured by the Earth’s rotation around the sun) and mean solar time (our 24-hour day).
On the reverse side, there is an annual calendar that displays not only the month and date, but also the sign of the zodiac. Ingeniously, all the functions of the watch can be set from the single crown. Simply pull it out completely, disconnecting the hour and minute hands, and the calendar function on the back of the watch can be adjusted to the correct date. This simultaneously adjusts and sets the position of the night sky and thus all sidereal (solar time) information.
The mechanism and winding device in the Astérium can be admired by simply turning it over and looking through the transparent sapphire crystal covering the entire movement.
The watch is regulated by Bovet’s patented double-face one-minute flying tourbillon, located at the base of the movement. The traditional balance wheel and balance spring are manufactured in-house, and the tourbillon cage is constructed with three evenly spaced pillars, allowing the seconds to be read from the small dial above the escapement.
Despite its diminutive dimensions, the movement has over 750 components. A number of the bridges and plates have been hand-decorated, and the angles and edges are all hand-polished. It is, in a sense, everything watchmaking should be, both a timekeeper for your every day and an imaginative scientific instrument informing the owner of their journey through the heavens aboard the spaceship Earth. Winner of this year’s GPHG Calendar & Astronomy prize. POA.
Find out more about the Bovet 1822 Récital 20 Astérium HERE.
Words: Dr Andrew Hildreth