Jaeger-LeCoultre’s Duomètre à Quantième Lunaire has won numerous awards and been heralded by collectors and enthusiasts, and today the manufacture in Le Sentier announces that this timepiece will be offered in a limited series of 200 pieces in white gold with a matte black dial. Find complete details, pricing and wallpaper inside.
The Duomètre à Quantième Lunaire incorporates Jaeger-LeCoultre’s latest horological achievements: it displays time with a jumping seconds hand – the so-called “Seconde Foudroyante” – showing 1/6th of a second increments and additionally providing the date and the age of the moon in a separate sub dial. But the truly novel aspect of this watch lies in the Dual-Wing movement concept, which features two independent power supplies: one dedicated to timing – regulated by escapement and balance, and the other for the display of time – hour, minute and seconds hands, plus the date and the age of the moon for the Northern as well as the Southern hemisphere. Both are synchronized through the jumping seconds hand mechanism driven by the escapement.
The driving force behind the design is timekeeping accuracy. The Dual-Wing concept addresses an age-old problem in watchmaking: every complication reduces the amount and consistency of the energy reaching the escapement. The more regular the energy flowing to the going train and escapement, the better the chances for highly precise timekeeping.
Jaeger-LeCoultre is no stranger to innovation or to high-precision timekeeping. In recent years the manufacture has produced the Gyrotourbillon I with its spherical tourbillon, the Master Minute Repeater with its unique sound system, the Reverso grande complication à triptyque, the most complicated swivel-watch, the Master Compressor Extreme LAB, the first watch running completely without lubrication, and the Hybris Mechanica à Grande Sonnerie. The Grande Maison also took the top two spots at the 2009 International Chronometry Competition.
The Dual-Wing movement design also cuts a new path. The caliber is divided into two sections or two wings – hence the dual-wing name. On each side sits one barrel with its mainspring guaranteeing a power reserve of 50 hours: one for hour, minute, seconds, jumping seconds, the date and the age of the moon, the other for the escapement device to ensure a constant power supply. Both springs are wound through the crown: rotating it clockwise, winds the timing barrel (escapement), turning the crown counter-clockwise winds the power reserve of the functions (hour, minute, seconds, jumping seconds, date, moon phase).
Caliber 381, visible through the sapphire caseback, features a large balance wheel of 10 millimeters in diameter and an inertia of 11.5 mg cm2 beating at a frequency of 21,600 vibrations per hour or 3 Hertz.
The watch features two seconds hands. One at the center and a second one at 6 o’clock: a jumping seconds hand accurate to 1/6th of a second. Setting the time is easily performed by pulling the crown: then both seconds hands, the center seconds hand and the jumping seconds hand jump to the zero-position leaving the escapement running. Pushing the crown activates both hands simultaneously by re-coupling into the running escapement. Most timepieces stop the seconds by freezing or holding the balance wheel, usually by friction when an arm comes into contact with the wheel’s rim. When the friction is released, the balance wheel requires some time to get back into rhythm, which can affect timekeeping by several seconds.
The mechanism behind the two hands is based on two escape wheels fixed to the same axis: one works with the lever while the other is driving the seconde foudroyante through the jumping seconds star. Upon pulling the crown, a lever is stopping the jumping second when it reaches the zero-position. At the same time a “return to zero” hammer pushes the central second’s hand to the 12 o’clock position through the use of a seconds heart cam.
The Caliber 381 exhibits a high degree of functional and aesthetic finishing. The two independent barrels are snailed and beveled by hand, while the ratchet-wheels are brushed with sunray-patterns and engraved and gilded “Mouvement” and “heure/minute” indication respectively. The hand-beveled bridges, as well as the polished sinks distinguish between the standard watch mechanism and the date-moon-complication in the dual-wing concept: the bridges of the first are held in taut, straight shapes and the latter in arabesque motives. The going trains are circular satin-brushed. The wheels and pinions feature snailed and polished surfaces. Flame-blued steel screws and a base plate of untreated nickel-silver highlight traditional finishing techniques.
The 42mm case, waterproof to 5 bar, uses a push button at 10 o’clock to set the date and a pusher between the lugs at 12 to adjust the moon phase. Matte black or chocolate brown alligator straps are fitted to a double folding clasp.