Luna Magna Gold
Luna Magna Gold
- Limited editon
- Alligator leather strap
- 30 meters water resistance
- 44 mm case
The volume of the moon
In a starry sky, a large moon alternates between light and dark as it moves through its phases. Here, Arnold & Son presents its first three-dimensional moon made of marble and aventurine. Showcased on an aventurine glass dial, the moon changes majestically and with astronomical precision. It is the largest rotating moon ever built into a wristwatch, and a creation that benefits from the first-class watchmaking and decorative techniques of the Arnold & Son Manufacture.
Luna Magna features Arnold & Son’s first three-dimensional moon. With this original timepiece, the Swiss watchmaker with English roots aims to make a lasting impression by presenting the largest rotating moon ever created in relief for a wristwatch. Beneath an off-centred dial at 12 o’clock, which constitutes one of the house’s aesthetic signatures, Arnold & Son has placed a rotating sphere that accurately represents the appearance of the quarters of the moon against a starry backdrop that is more dazzling than a midsummer night sky.
Presented in a 44 mm red-gold case, Arnold & Son has recreated one of its distinctive designs. The off-centred hours and minutes dial at 12 o’clock frees up substantial space for displaying complications, such as this spherical moon measuring 12 mm in diameter. Its size is not its only distinctive feature. Half of the moon is made of marble to represent the illuminated part of the Earth’s satellite, while the other half is made of aventurine glass to depict the darker side. Neither material has ever been used in a three-dimensional design such as this. Changing from dazzling white to a deep, starry blue, the Luna Magna’s quarters have been delicately depicted to replicate the appearance of the lunar disc.
The large moon emerges from the main plate of the A&S1021 calibre without upsetting the overall balance of the timepiece. Arnold & Son has drawn on its remarkable creativity to make Luna Magna a well-proportioned watch that showcases the incredible volume of its moon.
The lunar globe thus appears halfway up the movement, perfectly positioned between the top and bottom. The upper part is encased in a glass box. This technique has been repeated on the case-back side, where the sapphire crystal rests on the wrist.
By placing most of the volume in these sapphire crystals, the Luna Magna’s case has a total height of 15.9 mm.
Lastly, to bring the overall piece together, the deeply tapered lugs extend the curvature of the sapphire crystal to meet the natural curve of the wrist.
Arnold & Son has an ancient, long-standing relationship with the phases of the moon. Guided by the life of John Arnold and the mark he made in the Royal Navy during the 18th century, the house has frequently endeavoured to depict the age of this satellite as accurately and as beautifully as possible. By completely reinventing the way the Earth’s satellite is depicted, Luna Magna elevates itself by pushing the boundaries of this astronomical and poetic watchmaking exercise.
Luna Magna is driven by the A&S1021 calibre, which has been fully developed, manufactured, assembled and adjusted in the Manufacture. This new hand-wound calibre, which has been designed with the lunar globe in mind, features a 90-hour power reserve and a regulating organ oscillating at a frequency of 3 Hz. The movement also includes a secondary display detailing the age of the moon on the case-back side. Its clearly readable markings are designed for high-precision adjustments.
The sophisticated celestial mechanics are also based on precise astronomical reality. In fact, the duration of a complete lunar cycle is 29 days, 12 hours, 44 minutes and 2.8 seconds. Arnold & Son has managed to replicate it in such a way that it will take 122 years for the movement’s display to deviate from the correct celestial reading by one day. The correction required at this time will be easy to dispense, as the Luna Magna’s moon-phase function can be accessed directly by the crown. This practical feature has been made possible by Arnold & Son’s total mastery of the watchmaking process.
- hours, minutes, astronomical three-dimensional moon phases (one-day correction required every 122 years), moon-phase indicator on the back
Calibre: A&S1021, hand-wound mechanical
Diameter: 37.60 mm
Thickness: 12.00 mm with three-dimensional moon (4.75 mm without moon)
Power reserve: 90 hours
- Frequency: 3 Hz / 21,600 vph
main plate: circular-grained
bridges: chamfered, with Côtes de Genève stripes radiating from the centre
wheels: circular satin-finished
screws: blued and chamfered, polished heads
moon-phase indicator: circular satin-finished
- aventurine glass
- white lacquered hours dial
- blue PVD flange
- 12.00 mm in diameter
- white marble half sphere and aventurine glass half sphere
Material: 18-carat red gold (5N)
Diameter: 44.00 mm
Thickness: 15.90 mm (with crystal)
Crystal: domed sapphire with an anti-reflective coating on both sides
Case back: sapphire crystal with an anti-reflective coating on the inside
- Water-resistance: 30 metres / 3 ATM
Material: hand-stitched blue alligator leather
- Buckle: pin buckle in 18-carat red gold (5N)
Limited edition: 28 timepieces
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.