Perpetual Moon 38 Gold Cliff Grey

Blue Aventurine & Cliff Grey Editions

Between Earth and Heaven

Perpetual Moon 38 Red Gold welcomes two limited-edition dials. The radiance of 88 pieces in blue aventurine glass and 28 pieces in a warm, sunray-brushed grey joins that of the largest moon phase. Arnold & Son exhibits its mastery of colour, its sense of texture and its taste for materials, telling a nocturnal narrative that brings together the grey of a cliff, the iridescent white of the moon and the almost black blue of a starry sky.

Blue aventurine glass and cliff grey. Two new themes take hold of the 38 mm diameter red gold (5N) iteration of Perpetual Moon,giving two sophisticated dials befitting of the precise astronomical moon phase of the A&S1612 calibre. 

From the outset, Perpetual Moon 38 was destined to become a fully-fledged collection, distinct from its larger 41.5 mm diameter cousin and its more assertive style. Behind the scenes is the unwavering quality with which Arnold & Son creates its movements and selects the elements for their exteriors. 

White and green
Measuring 38 mm in diameter and 10.44 mm thick, the case of Perpetual Moon 38 Red Gold is brought to life from a block of red gold (5N). Its bezel, four lugs and crown are polished, shining under the cold light of the moon. The blue aventurine dial, constellated with metallic particles, blends into a celestial vault sculpted from the same glass. The "cliff grey" dial, in a warm, sunray-brushed grey, boasts an ever-shifting moiré effect under a grained matte midnight blue sky. 

These two limited editions of Perpetual Moon 38 Red Gold are home to a huge moon phase. This luminescent disc of mother-of-pearl illuminates the sky, framed by the constellations of Cassiopeia and Ursa Major.  

A 38 mm picture of precision
Perpetual Moon 38 Red Gold transposes the watchmaking requirements that have always guided Arnold & Son into its slender case. The Arnold & Son Swiss manufacture has designed an entirely new calibre, the smallest in its collection, and dedicated it to Perpetual Moon 38. 

At 30 mm, the A&S1612 calibre has been sized to fit the diameter of the case. The hand-wound movement continues Arnold & Son's tradition of calibres with long power reserves, reaching 90 hours. 

Waxing moon, waning moon
The star complication of the A&S1612 calibre is its moon phase. Perpetual Moon 38 showcases a large moon disc. The different crescents occupy the large aperture between 10 and 2 o'clock, with the form of their cut-out faithfully recreating the appearance of the moon.  

True to its tradition of precision watchmaking, Arnold & Son has given this moon phase an accuracy of 122 years. Continuously rising, it will take more than a century for this moon to lag one day behind the real one in our skies. 

Technical specifications

Functions                     

• hours, minutes, astronomical moon phases

Movement

• Calibre: A&S1612, hand-wound mechanical
  
• Jewels: 24
  
• Diameter: 29.4 mm
  
• Thickness: 4.95 mm
  
• Power reserve: 90 hours
  
• Frequency: 3 Hz / 21,600 vph
  
• Finishes               
  mainplate: rhodium-plated, radiating Côtes de Genève stripes
  bridges: polished and chamfered 
  wheels: circular satin-finished
  screws: blued and chamfered, polished heads                                    

Dial                               

• sunray-brushed “cliff grey”

Moon phases                

• sky: blue aventurine glass or grained midnight blue PVD
• constellations: overlaid with Super-LumiNova, hand-painted details
• moon: mother-of-pearl overlaid with Super-LumiNova, hand-painted details

Case

• Material: 18-carat (5N) red gold 
  
• Diameter: 38 mm
  
• Thickness: 10.44 mm
  
• Crystal: domed sapphire, with an anti-reflective coating on both sides 
  
• Case back: sapphire crystal, with an anti-reflecting coating
  
• Water-resistance: 30 m / 3 ATM 

Strap

• Materials: warm grey alligator leather, hand-stitched  
  
• Buckle: pin buckle, 18-carat (5N) red gold 

References

• grey: 1GLBR.U02A.C283A                                   

Edition 

• grey: 28 timepieces
  

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.