Longitude
Longitude Titanium is a COSC-certified chronometer with a power-reserve display and an imposing seconds counter paying tribute to John Arnold’s marine chronometers and his decisive role in calculating longitude at sea.
A celebration of watchmaking ingenuity
The architecture of this calibre is inspired by that of the timekeeping instrument driven by the first tourbillon created by Abraham-Louis Breguet in 1808, based on a chronometer movement designed by John Arnold. This first tourbillon regulator, now in the British Museum, was given to John Roger Arnold by the Paris-based watchmaker in honour of his scientific collaboration and friendship with his father. The Constant Force Tourbillon 11 timepiece, designed to mark the end of the 260th anniversary celebrations of John Arnold’s legacy, pays tribute to the watchmaker’s ingenuity and his close association with Abraham-Louis Breguet.
A calibre worthy of the master of chronometers
The A&S5219 movement was specially developed by the Manufacture’s engineers and watchmakers to the specifications of the Constant Force Tourbillon 11 watch. To remain as faithful to the original movement as possible, this calibre is hand-wound. But while inspired by the past, it remains thoroughly contemporary. It is equipped with two identical barrels mounted in series, giving a 100-hour power reserve. These barrels alternate in driving the mechanism, the second being activated when the torque of the first falls below optimum output.
A constant force mechanism
To guarantee the isochronism of the regulating group over 100 hours of operation, the movement’s designers incorporated a patented constant force mechanism between the going train and the tourbillon. Visible on the dial side, its purpose is to smooth out the energy delivered by the barrels so as to prevent excessive or insufficient torque from affecting the oscillations of the balance in the tourbillon carriage. This constant force mechanism is held in place by an 18-carat yellow gold bridge and rotates over the course of one minute. In the Constant Force Tourbillon 11, it replaces the fusee-and-chain configuration used by John Arnold in his chronometers. As well as supplying a constant force, the system chosen for this timepiece also allows for a ‘dead-beat seconds’ indication, in which the direct-drive hand does not advance seamlessly, but instead makes successive jumps of exactly one second – much like the direct-drive seconds of marine chronometers, which also made very similar jumps (detent chronometers generally beat every half-second).
The collection
Other collections in Chronometry
Discover collection
Nebula
Since their creation, the fully skeletonised Nebula collection in 38, 40 and 41.5 mm has been a star bursting with light.
Ultrathin Tourbillon
Ultrathin Tourbillon is one of the slimmest in the world. Presented in its purest expression, nothing distracts the eye from the hypnotic workings of the one-minute flying tourbillon.
Time Pyramid
By arranging the organs of Time Pyramid‘s movement from top to bottom instead of in a circle, Arnold & Son goes beyond the chronometric horizon to achieve an unparalleled feat of design.
DSTB
DSTB, which stands for ‘Dial-Side True Beat’, is one of Arnold & Son’s most personal collections, revealing its true-beat second’s mechanism on the dial side.
HM
The HM Collection is a tribute to timeless refinement, where sleek design meets exceptional craftsmanship.
