Longitude Titanium Fern Green

295 000 kr


Longitude Titanium Fern Green

  • 42.5 mm case
  • Titanium bracelet or rubber strap
  • 100 meters water resistance

Longitude Titanium

High-sea watchmaking

Arnold & Son, a benchmark in classic fine watchmaking, is exploring uncharted territory on the map of horology. Longitude Titanium is a sports-chic COSC-certified chronometer with a 42.5 mm titanium case. The dial of Longitude Titanium is vertical satin-finished in a continuation of the bracelet’s finish, which is subtly intersected by the polished edges of its links. With a power-reserve display at 12 o’clock and an imposing seconds counter at 6 o’clock, Longitude Titanium pays tribute to John Arnold’s marine chronometers, his revolutionary vision and his decisive role in calculating longitude at sea.

The aesthetics and construction of John Arnold’s marine chronometers were necessarily classic and functional, and were adapted to the harsh conditions of the high seas. Longitude Titanium, a contemporary interpretation of the great English watchmaker’s work, coherently combines this naval heritage with a refined design and highly resistant materials. The movement’s ‘chronometer’ certification is an essential addition to this scene, with its historical ties to Arnold’s creations and his quest for accuracy.

Ergonomic spirit

As a natural consequence of this maritime identity, Longitude presents a titanium case whose curves and profile are directly inspired by the design of contemporary sailing boats. The case middle is taut like a ship’s waterline, while the case back is basin-shaped like a keel. The base of the bezel – the ship’s rail – is graduated with 60 notches, echoing the fluted ring of John Arnold’s marine chronometers. The finishes – polished on the flanks and satin-finished on the flat surfaces – continue this high-sea influence. The crown, protected by a shoulder, is screwed down to guarantee water-resistance to 100 metres.

Curved spirit

With its flowing curves, Longitude Titanium is both comfortable to wear and a joy to behold. Each of the series is fitted with an integrated titanium bracelet. Everything is rounded with no straight lines, even in the finer details as the links themselves are domed. The succession of gentle curves and combination of polished and satin-finished surfaces are a continuation of the case’s identity. Longitude Titanium is complemented by an interchangeable system and comes with an additional rubber strap.

Watchmaking spirit

The dial of Longitude Titanium has been designed in a graphic and historical spirit. This graphic aspect can be seen in the satin-finished, polished and luminescent hour-markers that recall the shape of the bracelet links. It is also graphic in the display of its indications, which are aligned with the vertical axis of the dial: a mirror-polished power-reserve indicator shown by cut-outs in the dial at 12 o’clock, the hour and minute hands in the centre, and the imposing small seconds at 6 o’clock. However, this layout was also chosen for its ties to John Arnold’s marine chronometers, as it was he who introduced this arrangement and established it as standard.

Chromatic spirit

Cornwall, John Arnold’s birthplace, inspired the colours of the Longitude dials. The first edition, limited to 88 timepieces, is adorned with a sandy golden shade called ‘Kingsand’ in reference to the eponymous beach, which is one of the county’s hidden jewels. The second version sports an ocean blue, while the third and final series is a fern green.

Inventive spirit

During the 18th century, maritime trade was the main source of wealth. New routes opened up on the three major oceans, offering vast prospects. However, high-sea navigation was hampered by as yet incomplete maps and charts and, above all else, by inaccurate longitudes, i.e. the position of boats on the east/west axis. In 1714, the British Parliament passed the Longitude Act, which offered a prize of twenty thousand pounds to anyone who could develop a simple and dependable method for determining the longitude of a ship at sea. Briton John Harrison thus invented the marine chronometer, which would be used for centuries to come. His method involved measuring the difference between the local time on the boat, by finding solar noon, and the time of an onboard precision clock capable of keeping the time at the port of departure. John Arnold developed, improved and simplified the principles presented by Harrison. He started to supply his marine chronometers in 1771, which were more robust, affordable, extremely accurate and would go on to become essential to high-sea navigation.

Kinetic spirit

At the heart of Longitude Titanium beats the new A&S6302 calibre, certified by the Contrôle Officiel Suisse des Chronomètres (COSC). It is wound by an oscillating weight with a design influenced by sailing. Its shape is reminiscent of the prow of an 18th-century English frigate cleaving through the water, and it is carved from a single block of 22-carat gold. Its felloe is engraved with graduations similar to those on a sextant – another maritime element.

Mechanical spirit

The calibre is lavished with the same high standard of finishes commonly seen at Arnold & Son, such as chamfered bridges with the house’s specialty ‘Rayons de la Gloire’ motif. Like all its movements, the A&S6302 was entirely developed, produced, decorated, assembled, adjusted and cased up at the Manufacture in La Chaux-de-Fonds. This calibre features a large barrel and an oscillation frequency of 4 Hz, providing a 60-hour power reserve.

Technical Specifications


  • hours, minutes, small seconds, power reserve


  • Calibre: A&S6302, self-winding mechanical, COSC-certified
  • Jewels: 36
  • Diameter: 33.00 mm
  • Thickness: 6.65 mm
  • Power reserve: 60 hours
  • Frequency:4 Hz/28,000 vph
  • Finishes                                
    main plate: palladium finish, circular-grained
    bridges: palladium finish, polished and chamfered, ‘Rayons de la Gloire’ motif
    wheels: golden finish, circular satin-finished
    screws: blued and chamfered, mirror-polished heads
    oscillating weight: 22-carat red gold (5N), skeletonised, chamfered, engraved


  • Fern green PVD treatment, vertical satin finish
  • power reserve: blue PVD treatment, golden finish or rhodium-plating, mirror-polished
  • small seconds: snailed
  • hour-markers: rhodium-plated or golden finish, coated with Super-LumiNova
  • hands: rhodium-plated or golden finish, skeletonised, coated with Super-LumiNova


  • Material: titanium
  • Diameter: 42.50 mm 
  • Thickness: 12.25 mm (with crystal)
  • Crystal: sapphire, anti-reflective coating on both sides
  • Case back: sapphire crystal, anti-reflective coating
  • Water-resistance: 100 metres/ 10 ATM 
Interchangeable bracelet
  • titanium, folding clasp

Additional Strap

  • blue or green rubber, titanium pin buckle


  • fern green: 1LTAT.F01A.N001U


  • fern green: not limited


    As a contemporary Swiss watch brand, Arnold & Son continuously reinvents its approach to pay homage to the work of John Arnold, a man who provided solutions to the challenges of his era, notably the accuracy and reliability of timepieces. As a renowned watchmaker, he produced some of the most accurate marine chronometers of the 18th century and won several awards from the Bureau des Longitudes, spurring him on in his research into timekeeping. As an inventor, he filed a number of patents, including one for a compensation balance featuring a bimetallic balance-spiral (1775) and another for a helical balance spring with terminal curves (1782). He also produced simplified chronometer design principles that permitted mass production of these timepieces, a number of which were made available to His Majesty’s Royal Navy, making John Arnold one of its principal suppliers. One of his least known but most significant contributions was the modern definition of the term ‘chronometer’, which today refers to a high-precision timepiece driven by a movement that has passed an accuracy inspection carried out by an official neutral body.


    A Fine Watchmaking House stands out for its mastery of the classics. Arnold & Son has based its identity on its ability to produce fine watchmaking complications that are linked to the heritage of John Arnold. These include true seconds (or dead-beat seconds) – a function recalling the escapements of pendulum clocks marking out the seconds – and dual time zones driven by twin regulating organs, which hark back to the original method of maritime positioning. The moon-phase displays also illustrate the brand’s mastery of the classics, while revealing a more unconventional side through the use of large moons in sculpted gold. Lastly, the power reserves of up to eight days offered by Arnold & Son pay homage to marine chronometers, which also benefited from an impressive autonomy.

    The twenty or so calibres presented to date by Arnold & Son have all been conceived, designed, developed, machined, decorated, assembled and adjusted by its sister Manufacture, La Joux-Perret. This independence and creativity demonstrate the House’s ability to perpetuate John Arnold’s exceptional inventions.


    The style of Arnold & Son timepieces is instantly recognisable. The three-dimensional architecture of their movements, the late-18th-century-style cantilever balance-cocks, the George-V-style bridges, the constant quest for multiaxial symmetry and the artfully crafted guilloché dials go hand-in-hand with openworked components, from a single barrel to the full range of grande complication calibres.


    Arnold & Son’s remarkably balanced collections are all produced in limited series and distributed around the world through carefully selected points of sale. They are priced fairly, because excellence is bound to honesty.

    As Swiss watches with English roots, they stand out without being ostentatious. Arnold & Son timepieces are a delight for the eyes and the mind, and are aimed at customers who are looking for something unique.

    Astronomy, Chronometry and World Time

    Arnold & Son's three founding principles

    Throughout human history, measuring time has always referred to the stars. It was by observing certain stars and understanding their cycle that the first calendars were established with impressive accuracy. It took several millennia before this precision was enclosed in a timepiece like the ones designed by John Arnold. 

    The golden age of maritime explorations and discoveries ushered this precision into a new technical ideal – determining longitude at sea. Its immediate corollary was the identification of local time, which changed constantly as the observer moved along an east-west axis. Astronomy, chronometry and what we now call world time are thus inextricably linked within one and the same question, to which John Arnold and his son devoted their lives, their art and their genius. 

    This is how these three dimensions – astronomy, chronometry and world time – have come to be embodied in the House's contemporary timepieces.  Echoes of John Arnold's inventions and preoccupations, these pillars represent the foundations on which the Arnold & Son collections are based.

    Chronometry: Be accurate

    Rate accuracy, which is known as chronometry, is the key requirement of Arnold & Son's contemporary watchmaking. It is the standard of excellence for its collections, the first condition to be met and constantly checked, whether it is at the forefront or in the background of a watch designed by Arnold & Son. It is the most discreet of a movement's characteristics. 

    When building an Arnold & Son collection, all the thinking is focused on this chronometry. The manufacture calibres are based on advanced technical fundamentals that are not necessarily the best known. One of them is the choice of small, lightweight balances capable of rapidly returning to their isochronous rate after the latter has been disturbed by inevitable everyday shocks. Another is the routine use of large barrels or even two series-coupled barrels to store the energy required for the movement to function.  They consequently provide Arnold & Son's manual winding calibres with above-average power reserves of 90 hours and more. A third is the particular attention paid to manufacturing the gear trains, roller-burnishing the pinions and polishing the gear teeth, as well as the precision of the machining and therefore the relative positions of the moving parts, a key concept in rate accuracy.

    The tourbillon (or the fact of putting the regulating organ in rotation on its axis to best adjust the effects of gravity on the balance and its hairspring) was patented after John Arnold's death, but it was undoubtedly at the heart of his chronometric research and discussions with his friend Abraham-Louis Breguet, who incidentally assembled his first tourbillon on a John Arnold pocket watch in homage to this great watchmaker. Nowadays, the tourbillon has become a must in Arnold & Son collections.

    While the tourbillon was not a complication in John Arnold's time, constant force underpinned the design of his marine chronometers. The regularity of the rate of the sprung balance relies on the consistency of the energy that it receives. However, this naturally fluctuates due to the circular and spiral nature of the mainspring contained in the barrel. To achieve a perfectly smooth torque, in other words a constant force, Arnold & Son uses a one-second constant-force mechanism. Housed just before the escapement, it stores up a small but always equal amount of energy in a secondary spring, the remontoire. Thus, every second, the sprung balance receives very precisely the same force to power its oscillations. These become more even, thereby creating the conditions for a high-precision rate.

    Arnold & Son also works with another of John Arnold's historical chronometry indicators: deadbeat seconds, a mechanism that was indispensable to navigators at the time for calculating longitude. This mechanism advances one step each second, rather than six or eight smaller jumps in sync with the frequency of the balance. Instead of the term deadbeat seconds, Arnold & Son prefers a name whose very sound means accuracy: “true beat second”. Its jump is a signature of John Arnold's marine chronometers and a complication that is still alive and well in the House's collections.

    Astronomy: Under the sky

    The Pole Star, Southern Cross, astrolabes and sextant: measuring time has relied on the recurrence of astronomical phenomena in order to find long, reliable points of reference there that can be used under any conditions. The fruit of the human ingenuity, patience and dedication of countless observers and astronomers from every culture, these markers of cyclical time are foundational for Arnold & Son watchmaking.

    Astronomical complications are a signature of Arnold & Son collections, with the moon as the heavenly body of choice, main subject and major inspiration. The distinctive feature of the Brand's moon phase timepieces is that they feature “astronomical” display precision as a matter of course. This term corresponds to an accumulated one-day deviation in the moon phase display every 122 years. Since setting this complication requires great finesse, the Arnold & Son moons generally have a double display with a secondary indicator on the case back next to the movement. This extremely rare display bears witness to Arnold & Son's involvement in all types of development and reflects its favoured themes, which are as much chronometric as astronomical.

    Over and above their precision, Arnold & Son's moon phases attract all the light, either with a large moon opening up over half the dial, or with a 12-mm three-dimensional rotating moon, making it the largest of all moons. Whether in two or three dimensions, the moon is always treated as a small work of artistic craftsmanship, composed of materials that are rare in watchmaking such as marble or Paraíba tourmaline, or delicate such as mother-of-pearl, meteorite or aventurine glass. The Arnold & Son moon also shines at night, often with a subtle addition of luminescent material. 

    World Time: Here, elsewhere, everywhere

    With ocean navigation, humankind divided up the world and invented longitudes, which were calculated by comparing the local time, observed using the sun, and the time at a starting point, kept by an extremely reliable timepiece. John Arnold was one of the leading suppliers of chronometers to the British Navy. He was the one who successfully improved the reliability and simplified the production of these indispensable marine chronometers, so much so that he became a benchmark among great explorers such as James Cook and later Dr David Livingstone. The indication of several time zones is therefore integral to Arnold & Son's watchmaking identity.

    As this navigation was itself inseparable from cartography, for this world time complication Arnold & Son has chosen to depict a three-dimensional terrestrial hemisphere, making it possible to tell what time it is at any point.

    In parallel to this graphic vision, Arnold & Son has developed a second approach to the time elsewhere in the world: with a double tourbillon featuring two distinct rotating regulating organs, making it possible to follow time zones offset by 15, 30 or 45 minutes compared to a full hour – a freedom in terms of setting that remains extremely rare. 

    Once again, and because this double display is based on a profoundly chronometric complication, Arnold & Son’s fundamental principles are interwoven. One never advances alone; there are always two – if not three – together. This is how a pillar's strength is measured: it relies on the next one, creating the conditions for a solidity that stands the test of time.


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