Jaeger-LeCoultre is celebrating Her Majesty Queen Elizabeth II’s sixty years on the throne by creating a special Atmos du Millénaire clock issued in a limited edition of three pieces with Her Majesty Queen Elizabeth’s lineage engraved on.

Displaying the hours, months and perpetual moon phase, this celestial millennium-bestriding mechanism, is destined to measure out the years one by one until 3000.

The indication of the years celebrates the virtues of the quasi-perpetual movement: all the years from 2000 to 3000 are marked around the dial in concentric circles.

The months are displayed in the aperture above the circle of the hours, while the moon phase indicator is positioned at 6 o’clock.

Sticklers for absolute precision, Jaeger-LeCoultre’s master clockmakers also take the trouble to remind the Atmos’s owner that it will need to be reset periodically – the moon-phase indicator is only accurate to a day every 3,821 years.

Invented in 1928, the Atmos’s quasi-perpetual movement counts the hours, day after day, year after year, without any need for a battery or rewinding.

Its secret lies in the hermetically sealed capsule positioned at the back of the mechanism which can transform variations in ambient temperature into mechanical energy.

Each time the latter rises or falls by a single degree centigrade, the mechanism is able to store up enough energy to guarantee 48 hours of function.

Only the balance’s extremely slow oscillating speed and its suspension from an incredibly fine elinvar wire guarantee the mechanism’s ability to continue functioning unassisted across the centuries.

ALthough the Atmos is the largest mechanism produced by Jaeger-LeCoultre, it uses scarcely a 240th part of the energy required by an ordinary wristwatch!