ith its “Colours of the Moon” series, Arnold & Son showcases astronomy. Presented in limited editions of 18 pieces each, these three steel versions introduce a world first in watchmaking: the use of mother-of-pearl coloured using a PVD process for both the dial and the moon phase sky. Dedicated to our natural satellite, they feature a mother-of-pearl moon-phase disc with remarkable astronomical precision. It is luminescent and crafted in three shades inspired by the changing hues of the Moon in certain seasons or under exceptional conditions.

The moon played a discrete but decisive role in John Arnold’s career. In 1768, after presenting King George III with a sophisticated watch ring, the watchmaker came to the attention of the Astronomer Royal Nevil Maskelyne, who was researching solutions for calculating longitude using the lunar distance method. Rather than copying John Harrison’s famous H4, Arnold decided to innovate and develop his own marine timekeeper. Impressed by the precision of Arnold’s work and a watch he had recently altered at his request, Maskelyne trialled it on a scientific expedition to the West Indies in 1769. This recognition led John Arnold to offer the Board of Longitude a chronometer – a term he invented himself – that was accurate, affordable and reproducible, designed for use at sea.

The fifth-largest satellite in the solar system, the Moon has fed the human imagination since the beginning of time. The regularity of its cycles made it humanity’s earliest measure of time, long before the rise of scientific astronomy.

From an astronomical perspective, a lunation – the time between two new moons – lasts on average 29 days, 12 hours, 44 minutes and 2.8 seconds. The full moon marks the culmination of this cycle, and its changing colours have fascinated civilisations around the world throughout history. Depending on its position in the sky and the season or atmospheric conditions, our satellite can assume surprising hues.

It is from these celestial phenomena that Arnold & Son drew inspiration for the “Colours of the Moon” limited editions. The Blue Moon evokes both the rare occurrence of an additional full moon within a single season and the cool tones that certain atmospheric particles can impart to it. The Golden Moon recalls the warm glow the Moon takes on when low on the horizon, its light filtered by the Earth’s atmosphere, a sight often associated with harvests and folk traditions. As for the Red Moon, it alludes to lunar eclipses, when the Earth casts its shadow across the Moon, and only the Sun’s red rays pass through the atmosphere, giving rise to the spectacular “Blood Moon”, steeped in myth and symbolism in many cultures.

To enhance the moon, Arnold & Son has applied Super-LumiNova beneath the coloured mother-of-pearl representing it. On either side of the lunar disc, the constellations Cassiopeia and Ursa Major are hand-painted in the same luminescent material. These constellations were chosen as a tribute to the mariners who relied on them to locate the Pole Star, which indicates north.

Another distinguishing feature of these new “Colours of the Moon” models, which reinterpret the Perpetual Moon collection, is their stainless-steel case measuring 41.5 mm in diameter and 11.67 mm thick, giving this highly exclusive series, limited to just 18 pieces per version, a unique identity. The steel highlights the richness of the dial and the play of light across the moon phase while lending the watch greater versatility for everyday wear without diminishing its horological exclusivity.

Always seeking to innovate, Arnold & Son is the first watchmaker to employ a PVD (Physical Vapour Deposition) treatment with mother-of-pearl. Performed in a controlled vacuum environment, this process involves applying a thin metallic layer to the material to add depth and nuance. It provides the dials and moon-phase skies of the Perpetual Moon “Colours of the Moon” editions, in black, blue, or green shades with unique, changing reflections. As light passes through mother-of-pearl, it reveals the natural layers of this precious organic material. And as the light shifts in angle and intensity, the patterns that emerge recall the flowing grain of Damascus steel.

To bring this celestial mechanism to life while ensuring everyday timekeeping, Arnold & Son has equipped the three Perpetual Moon “Colours of the Moon” limited editions with its in-house A&S1512 manual-winding calibre. With a diameter of 34 mm and a thickness of 5.35 mm, this movement offers a generous 90-hour power reserve when fully wound.

Visible through the sapphire crystal case back, the calibre demonstrates meticulous attention to detail in its finishing, from the 3 Hz regulating organ to the bridges adorned with radiating Côtes de Genève and hand-bevelled edges, as well as the perlage of the main plate and the snailing of the wheels. This opening also reveals blued screws with polished, chamfered heads and a secondary moon-phase display with graduated markings, allowing precise adjustment of the astronomical display visible on the dial side.

In keeping with their striking aesthetic character, the Perpetual Moon “Colours of the Moon” timepieces are paired with hand-stitched alligator leather straps in matching tones. They are fastened with traditional pin buckles in the same stainless steel as the case.

TECHNICAL SPECIFICATIONS

Perpetual Moon 41.5 Steel Colours of the Moon

Functions hours, minutes, astronomical moon phases, secondary moon-phase display on the case back

Movement

• Calibre A&S1512, mechanical manual winding
• Jewels 27
• Diameter 34 mm
• Height 5.35 mm
• Power reserve 90 hours
• Frequency 3 Hz/21,600 vph
• Finishes main plate: rhodium-plated and circular-grained bridges: chamfered, radiating Côtes de Genève wheels: snail-finished screws: blued and chamfered, polished heads secondary moon-phase display: rhodium-plated and rimmed

Dial

• material: PVD treated mother-of-pearl in black, blue or green
• sky: PVD treated mother-of-pearl in black, blue or green
• constellations: hand painted, added with Super-LumiNova
• moons: mother-of-pearl discs tinted red, gold or blue added with Super-LumiNova

Case

• Material stainless steel
• Diameter 41.5 mm
• Thickness 11.67 mm
• Crystal domed sapphire with a double-sided anti-reflective coating
• Case back sapphire with an anti-reflective coating
• Water resistance 3 bar (30 m/100 feet)

Strap

• Material black, ink blue or Cornwall green alligator leather
• Buckle pin buckle, stainless steel

Limited edition 18 pieces for each reference

Reference black: 1GLBS.M02A.C672S blue: 1GLBS.M03A.C263S green: 1GLBS.M01A.C1242S

Swiss retail price CHF 21,100 incl. VAT (subject to change)