In 2007, Jaeger-LeCoultre premiered the Duometre concept in a chronograph, which epitomises the concept of precision.
Its lightning-fast operation, which can time intervals as precise as 1/6th of a second, contrasts with the slow rhythm of the lunar cycle (29.53 days) in the new Duometre Chronograph Moon sized at a diameter of 42.5mm.
The elegant case, recalling those of 19th-century savonette pocket watches, is in platinum or pink gold and paired with a copper-coloured or silver dial featuring an opaline finish.
The two versions are equipped with the new manually-wound Calibre 391, revealed beneath the sapphire crystal caseback. Much of the complex movement is open-worked and bridges, decorated with sunrayed Geneva stripes, seemingly float above levers and wheels.
On the dial, a counter at 6 o'clock is a stage for the seconde foudroyante (flying second), which performs when the chronograph mechanism is activated.
A hand makes a complete rotation in one second, during which it beats six times. When the timer is stopped, the whirling dance ends instantaneously and thus providing a reading accurate to 1/6th of a second.
Manually-wound Jaeger-LeCoultre Calibre 391.
A tachymeter scale further enables measuring speed based on the time taken to travel a fixed distance, or to calculate distance based on speed.
At 3 o'clock, the chronograph hours-minutes sub-dial also houses the moon phase display, while at 9 o'clock, the night-day indicator appears on the time-telling counter.
The symmetric layout is complemented by open-worked sections on the lower part of the dial that further offer glimpses of the mechanism.
On an arc-shaped bridge, two power reserve indicators reflect on the Duometre with two sets of barrel and gear trains -- each providing a power reserve of 50 hours.
Jaeger-Lecoultre's engineers have simplified the winding via a single crown -- forwards for the timekeeping barrel and backwards for the other one driving the mono-pusher chronograph and moon-phase complications.
Openworked sections on the dial offer glimpses of the mechanism.
