In 2007 Jaeger-LeCoultre launched the ground-breaking Duometre mechanism in the form of a chronograph – the complication that epitomises the concept of precision.
In 2024, the Maison applies the Duometre concept in an entirely new timepiece, marrying the high precision of a chronograph with the charm of a celestial complication. Powered by the new Calibre 391, the Duometre Chronograph Moon presents an intriguing contrast between the lightning-fast operation of the chronograph – which can time intervals as small as 1/6th of a second – and the slow rhythm of the moon as it passes through its cycle in 29.53 days, complemented by a Night and Day display.
Jaeger-LeCoultre’s engineers started from the ground up to develop a fully integrated movement, the Calibre 391, that combines a manually wound mono-pusher chronograph with moon phase and night-day complications, as well as two power reserve indicators and a seconde foudroyante (flying second) display.
When the chronograph mechanism is activated, the foudroyante hand begins its whirling dance, making a complete rotation in one second, during which it beats six times – stopping instantaneously when the chronograph timer is stopped and thus providing a reading accurate to 1/6th of a second.
On the dial side of the Duometre Chronograph Moon, two open-worked sections offer intriguing glimpses of the mechanism, hinting at the mechanical beauty of the calibre. On the reverse side, fully revealed beneath the transparent crystal case-back, much of the movement is open-worked and an array of bridges seems almost to be floating above the levers and wheels, drawing the eye deep into the mechanism. Creating visual unity across the entire expanse of the movement, the bridges are decorated with sunrayed Geneva stripes. It’s a challenging technique that demands absolute precision because the components must be decorated one-by-one, and yet radiate from the centre of the regulating organ to the edge of the calibre in perfect alignment once the movement is assembled.
The open-working of Calibre 391 serves two purposes: not only does it greatly enhance the aesthetics, it also serves a technical purpose, enabling the watchmakers to more easily assemble some parts of this highly complex calibre. This is a fine example of Jaeger-LeCoultre’s philosophy of marrying mechanics and aesthetics in such a way that each serves the other. Being a manually wound calibre, there is no winding rotor to conceal the chronograph levers.
At Watches and Wonders 2024, Jaeger-LeCoultre presents the Duometre Chronograph Moon in two variations: a platinum case contrasting with a copper-coloured dial, and a pink gold case offset by the discreet elegance of a silver dial. Both models are enhanced by a hand-stitched alligator strap with small-scale alligator lining.
