The monopusher chronograph’s split-seconds (rattrapante) and jumping seconds (seconde foudroyante) functions make it possible to freeze stopped times to 1/5 of a second. While the chronograph is running, a blued-steel hand on the subdial at 6 o’clock makes five jumps per second to complete each revolution along its scale. Thus, this hand precisely emulates the balance frequency of 2.5 Hz. The center-mounted gold chronograph hand and blued-steel rattrapante hand start to run, along with the jumping seconds hand, as soon as the right pusher (between 1 and 2 o’clock) is pressed. After each revolution of the sweep hands around the main dial, the minute-counter hand in the subdial at 12 o’clock advances by one interval.
When the left pusher (between 10 and 11 o’clock) is activated, the split-seconds hand stops to indicate the lap time while the chronograph hand keeps running. When the left pusher is pressed again, the split-seconds hand instantly catches up and remains realigned with the chronograph hand. Pressing the right pusher again will make all four chronograph hands stop, and pressing it a second time will reset them all to zero. Both the chronograph and rattrapante are controlled by column wheels, one for each function.
The perpetual calendar mechanism, based on the Gregorian calendar, not only knows how many days each month has in the course of a year, but also compensates for the 29 days of February in leap years. The calendar won’t require correction until the year 2100. The duration of each month is coded into a 48-segment wheel with recesses that are mechanically sampled by the date switching lever. The deeper the sampled recess, the shorter the current month.
Another special feature of the calendar is that it advances all displays, with the exception of the moon-phase, at midnight. The calendar indications are positioned at 3 o’clock (which indicates the date), 9 o’clock (the day) and 12 o’clock (the month and four-year cycle). The moon-phase, with its blue-enameled, solid-gold moon disk, is in the upper half of the jumping seconds dial at 6 o’clock.
The manual-wound, manufacture movement that powers all of these functions, Lange Caliber L1902, boasts an impressive amount of hand-finishing, including a black-polished finish on the chronograph levers and hand-engraved balance cocks. It also includes a Glashütte lever escapement, with a lever and escape wheel made of hardened 18k gold, based on an early invention of brand founder Ferdinand A. Lange. The balance spring is made in-house, and the fully wound mainspring offers a power reserve of 30 hours.
Lange has also lavished attention on the watch’s exterior, with a five-part white enamel dial, a railroad track minute scale, the aforementioned gold and blued-steel hands, and a 50-mm case (Lange’s largest to date) made of 18k rose gold. Only six pieces will be made, each on a red-brown, hand-stitched alligator strap, at a price yet to be determined.
For more on Lange’s new watches for 2012, check out the SIHH report from WatchTime’s Alexander Linz on his blog, Watch-Insider.com.
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