Luna Magna Ultimate I
Luna Magna Ultimate I
- Limited edition
- 44 mm case
- 30 meters water resistance
- Alligator leather strap
Luna Magna Ultimate I
A watch face featuring ruthenium crystals and a dial made of white opal. A bezel set with baguette-cut diamonds. A three-dimensional moon paved with blue sapphires and diamonds. The first chapter of the Luna Magna Ultimate series illustrates light, astronomical precision and the truly exceptional.
After presenting the Luna Magna, Arnold & Son set out to create a series of high-end jewellery interpretations of its three-dimensional moon model. In addition to the technical feat of placing a mechanical star measuring 12mm inside a watch, this piece displays superlative jewel-setting ability, both in the stones and techniques used. With paved and invisibly-set precious stones, Arnold & Son have applied their exceptional know-how to creating eight Luna Magna Ultimate I watches. Poetic and rare, they reveal an outstanding level of detail.
Only the most precious materials are used in the Luna Magna Ultimate I limited series. The case, measuring 44mm in diameter, is made of white gold and set with 7.62 carats of the highest quality diamonds. These include 20 baguette-cut diamonds on the case’s lugs, cut one by one to fit the unique shape of each mount.
A fine ring resembling the ring around Saturn constitutes the bezel, orbiting the Luna Magna Ultimate I case. It contains 112 baguette-cut diamonds totalling 5.90 carats. Light can enter freely, just as it would an open prism, thanks to the dual-row invisible setting which allows for radiance beyond compare.
Blanket of blue
The material used to make the watch face itself is just as exceptional, owing to its rarity. Hundreds of pure ruthenium crystals make up that sparkling blue façade. This extremely hard metal belongs to the platinum group, which means they are found together in the same ore. Separating them is a complex process that makes ruthenium ten times rarer. Here, it has been reshaped into crystals which are placed on the face plate before being blued.
Within the circle of blue radiance lies a dial in the conventional sense, featuring twelve Roman numeral markings, the Arnold & Son signature and the hands. This off-centre subdial owes its delicate colour to white opal, and its finesse befits a piece of the finest jewellery such as the Luna Magna Ultimate I.
Beneath the timepiece, the three-dimensional moon is the standout feature of the Luna Magna watches. Gem-setting of the utmost intricacy coats the entire white gold sphere. It is divided into 161 brilliant-cut diamonds for daytime and as many blue sapphires for night-time. The line between the two colours is a ripple of blue and white along the outline of the stones.
The Luna Magna Ultimate I is made with the A&S1021 calibre, which is entirely developed, manufactured, assembled and adjusted in-house at Arnold & Son. This hand-wound calibre, designed around the lunar globe, has a power reserve of 90 hours and a regulating organ at a frequency of 3 Hz. As for the case back, the movement provides a second display for the lunar phase, featuring easy-to-read graduations for utmost precision when correcting the lunar globe.
The sophistication of this celestial mechanism also lies in its astronomical accuracy. The length of a full moon cycle is 29 days, 12 hours, 44 minutes and 2.8 seconds. Arnold & Son has produced a likeness such that it would take 122 years for the movement to accrue a one-day interval between the watch display and the true celestial cycle. Nevertheless, this error is easy to correct given that the lunar function on the Luna Magna Ultimate I is directly accessible from the crown. Arnold & Son’s complete mastery of the watchmaking process allows for this practical touch.
- hours, minutes, astronomical moon phases (one-day correction required every 122 years), moon-phase indicator on the back
Calibre: A&S1021, mechanical with manual winding
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: Côtes de Genève stripes radiating from the centre, chamfered
wheels: circular satin-finished
screws: blued and chamfered, polished heads
moon-phase indicator: circular satin-finished
- dial: blue-treated ruthenium crystals
- subdial: white opal
12.00 mm in diameter meteorite with 18 carat white gold
set with 161 diamonds (~0.75 ct) and 161 sapphires (~0.85 ct)
Material: 18 carat white gold, bezel with dual-row invisible setting and studded lugs, with a total of 112 baguette-cut diamonds (~5.90 ct)
Diameter: 44.00 mm
Thickness: 15.90 mm (with crystal)
Crystal: box sapphire, anti-reflective treatment on both sides
Back: box sapphire crystal, anti-reflective treatment
Water-resistance: 30 metres / 3 ATM
- total weight: ~7.62 ct
- colour: D-E-F
- clarity: IF-VVS
total weight: ~0.85 ct
clarity: loupe clean
- Material : outside: blue or black alligator leather, inside: blue or black alligator leather hand sewn
- Buckle: pin, 18 carat white gold, set with 26 baguette-cut diamonds (~0.97 ct)
Limited edition: 8 pieces
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.