Imbued with the scientific spirit of the Enlightenment, Chronométrie Ferdinand Berthoud unveils a new experimental collection, combining the in-house tourbillon movement with a new display of the age and phases of the moon: the Chronomètre FB 1L.

The FB 1L Chronometer is a model displaying the age and phases of the moon. Combining chronometric precision and astronomical measurement, it associates these two previously dissociated values which jointly made it possible – almost three centuries ago – to achieve more accurate longitude calculations, a quest at the heart of a large number of Ferdinand Berthoud’s works.

The age and phases of the moon are two separate measurements.

The moon phase is the most common in watchmaking. This is the complication that visually indicates the different lunar cycles. The moon phase is divided into four phases: new moon, first quarter, full moon and last quarter. A lunation or lunar cycle is the time interval between two new moons. A symbolic and aesthetic complication, the moon phase does not, however, offer the accuracy necessary for astronomical use.

The age of the moon is a more accurate indicator which counts the number of days since the last new moon. This veritable scientific measuring instrument, coupled with the chronometric measurement of time, made it possible to determine longitude at sea with unparalleled accuracy nearly 270 years ago.

For the first time, the FB 1L collection combines these two instruments: a chronometer and an indicator of the age and phases of the moon within the same model.

The 100% in-house calibre of the Chronomètre FB 1L features an original suspended fusee-and-chain construction. It delivers a constant force to the escapement throughout the operation of movement, from its first turn of the crown to complete winding, thus achieving a 53-hour power reserve.

The movement also features a tourbillon with direct-drive seconds, compensating for the variations in rate induced by the different positions the watch adopts throughout the day. Direct-drive seconds are made possible by the correlation between the seconds wheel and the wheel driving the tourbillon carriage.

Finally, for the first time, Calibre FB-T.FC.L is complemented by a patented complication: the age of the moon. This consists of two indications. The first is the display of the moon’s age in days, marked from 1 to 14 on a sector swept over by a hand moving back and forth.  Day “1” is the first day since the new moon. Facing this “1” is a circle symbolising the latter. The next three quarters are spread over the same sector as the days go by. Facing the 14th day is a solid disc, symbolising the full moon. At this point, the hand performs a gradual backward move passing through the same quarters in the opposite direction: three quarters, two quarters, one quarter, until the return to the new moon.

This display of the age of the moon is complemented by another function revealed through a dial opening between 4 and 5 o’clock, showing the current moon phase, waxing or waning, thereby indicating whether the moon-age indicator hand is rising (up to day 14) or returning (to the new moon). Since this hand progresses at a rate imperceptible to the naked eye, this precious moon-phase indication makes it possible at a single glance to see whether one is heading towards a full moon or a new moon.

The accuracy of each movement in this collection is attested by a chronometry certificate issued by the Official Swiss Chronometer Testing Institute (COSC).

The unique features of the Ferdinand Berthoud movement are the subject of four patents, now supplemented by two other patent applications for the age-of-the-moon mechanism specific to the FB 1L models.

The distinctively shaped case is based on the architecture of the marine chronometers designed by Ferdinand Berthoud from 1760 onwards, inspired by his Marine Clocks, and their gimbal suspension in particular, which allowed the on-board chronometers to remain permanently in a horizontal position.

For the FB 1L collection, the case was completed for the first time with a selector switch placed between 4 and 5 o’clock which enables the wearer to choose between two positions, L and H, to set the age of the moon or the time.

Two versions of the Chronomètre FB 1L are available.

The FB 1L.1 “Near Side of the Moon” model favours a warm and luminous approach reminiscent of the visible face of the Moon and the intensity of the full moon. The piece has a case middle, side elements and crown in 18-carat polished white gold. Its lugs are made of black ceramic.

The FB 1L.4 “Far Side of the Moon” version evokes the dark and mysterious tones of the Moon’s hidden face. This time, its white gold case middle is sandblasted and, in place of ceramic, the lugs and side elements are made of dark grey ceramised titanium. On average four times harder than standard titanium, ceramised titanium is part of the sustainability approach adopted in the making of Ferdinand Berthoud creations, which has already led the Manufacture to develop a carburised steel with similar properties.

Each piece will be issued as a numbered ten-piece limited edition.

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