Jaeger-LeCoultre Duomètre Sphérotourbillon Moon

The Duomètre Sphérotourbillon Moon (also called Hybris Mechanica 12) is a tourbillon moon phase watch from Jaeger-LeCoultre.

Introduced at SIHH in 2015, the Duomètre Sphérotourbillon Moon was the sixth model in the Jaeger-LeCoultre Duomètre line. Closely related to the Cal. 382 Duomètre à Sphérotourbillon, this Cal. 389 movement adds a novel moon phase indicator concentric to the hands. This newly-developed moon phase complication is much more accurate than previous models, only needing adjustment after 3887 years.

Until this model, each member of the Duomètre family had been significantly different in design, even though all divide two barrels of power between independent functions of the watch movement. The Sphérotourbillon Moon is very closely-related to the Sphérotourbillon, with one mainspring barrel powering the gear train and complications while the other powers the tourbillon escapement. The Sphérotourbillon is a multi-axis tourbillon with numerous important technical achievements. In addition to the divided "Duomètre" double barrel power system, the Duomètre à Sphérotourbillon uses an unusual cylindrical balance spring and is the first tourbillon to include a stop seconds and zero reset feature for precise time adjustment. The tourbillon rotates on two axes: Every 30 seconds around the axis of the balance and every 15 seconds around a second axis, inclined 20º. Cylindrical balance springs have been seen in marine chronometer clocks before but it was not until the Jaeger-LeCoultre Reverso Gyrotourbillon 2 in 2008 that such a spring appeared in a wristwatch. This same concept is used in the Duomètre à Sphérotourbillon, with two terminal Breguet curves, one at each end of the spring.

Although the escapement does not stop as is common with hacking movements, a push-piece at 2 o’clock serves to stop the small seconds hand and bring it back to zero, according to the flyback principle. This had never before been achieved in a tourbillon. By allowing the escapement to continue its motion even as the gear train is stopped, the watch will not suffer from timekeeping fluctuations when the movement restarts.

Reference: 608.65.20 - 42 mm platinum, silvered dial Movement: Manufacture-manual winding movement caliber JLC 389, 21,600 A/h Sphérotourbillon with complete revolution in 30 seconds 2 combined movements: Carriage axis rotation speed: 15 seconds for a complete revolution Carriage rotation speed: 30 seconds for a complete revolution Cylindrical balance-spring Nickel silver bridges and mainplate 2 barrels 55 jewels 50 hours power reserve 476 components Case: Rose gold 42 mm, H 14,1 Sapphire crystal on both sides Waterproof to 50 m Dial: Hour (travel time-zone), minute and small second with flyback Power reserves (indications and movement) Annual calendar with hands 24-hour reference time-zone Moon phase indicator Sphérotourbillon Functions: Hand-sewn alligator leather strap with tang-type buckle Bracelet: