Imbued with the scientific spirit of the Enlightenment, Chronométrie Ferdinand Berthoud unveils in Baselworld 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. Truly at the crossroads between astronomy and chronometry, the Chronomètre FB 1L pays tribute to Ferdinand Berthoud’s work on chronometric precision and the calculation of longitude. It was to this end that the master watchmaker designed his famous Marine Chronometers, which inspired the creation of the FB 1L collection.
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.
18-carat white gold dagger-shaped facetted cut-out hours and minutes hands, rhodium plated 18-carat gold arrow-shaped power-reserve hand (on the back of the movement), rhodium plated bronze central seconds hands, polished steel lunar-cycle hand and fixed moon-phase index (4 o’clock).
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 age of the moon is a more accurate indicator which counts the number of days since the last new moon.
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 bracelet is in hand-stitched rolled-edge alligator leather made from a single piece of leather (115 x 75 mm, with a 20 mm buckle), with various sizes available on request. 18-carat white gold double-blade length-adjustable folding clasp. Pin buckle available on request.
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).
The original fusée and chain mechanism developed by the engineers of Chronométrie FERDINAND BERTHOUD occupies an exceptionally small space within the movement thanks to its “suspended” construction.
The barrel and fusée of Calibre FB-T.FC are linked by a chain comprising no less than 474 steel links, including more than 300 pins measuring barely 0.30 mm in diameter and all hand-assembled. The chain measures a total 28 cm long and the maximum tension exercised upon it once in place amounts to three kilos.
When the mainspring is associated with a fusée, the barrel drum turns in one direction when the spring winds down and in the opposite direction when it is wound up, thus causing the chain to wrap around the drum. A distinctive feature of Calibre FB-T.FC lies in the fact that its fusée mechanism has been equipped with an unusually designed differential gear.
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.
- Mechanical hand-wound Calibre FB-T.L
- 16 ½ lignes (diameter 37.30 mm – thickness 9.38 mm)
- 55 jewels
- Indications of hours, minutes, seconds, age and phases of the moon, power reserve on the back of the movement
- Suspended fusée and chain constant-force transmission regulation
- 3 Hz low-frequency tourbillon with direct-drive seconds
- 53-hour power reserve
- Movement precision and rate accuracy certified by the Swiss Official Chronometer Testing Institute
- Octagonal case in anthracite ceramised titanium & 18-carat sandblasted white gold featuring two transparent sapphire portholes
- Numbered edition 1/10 to 10/10
- Dynamometric crown (uncoupling system) in 18-carat sandblasted white gold
- Knurled anthracite ceramised titanium L/H (Moon/Time) selector, on the side of the case middle between 4 and 5 o’clock
- Screw-down case-back in 18-carat white gold fitted with a glare-proofed sapphire crystal
- Domed and arched sapphire crystal with anti-reflective treatment on both sides
- Moon plate (dial) in black PVD-coated sandblasted brass
- Hours and minutes in black PVD-coated brass counter at 12 o’clock, circular satin-brushed finish and matt in the centre
- Toothed feeler-spindle with steel spring at 9 o’clock
- Lunar cycles and age of the moon cartouche in satin-brushed black PVD-treated brass with grey-varnished engraved scale
- “Far side of the Moon” half-globe in engraved and rhodium-plated brass between 4 and 5 o’clock
- Flat inner bezel ring bearing the seconds around the dial rim, in black PVD-treated brass with grey-varnished engraved scale
- “CHRONOMÈTRE VAL-DE-TRAVERS SUISSE” inscription
- Hand-stitched rolled-edge alligator leather strap made from a single piece of leather (115 x 75 mm, with a 20 mm buckle) – Various sizes available on request
- 18-carat white gold double-blade length-adjustable folding clasp – Pin buckle available on request