Arnold & Son introduced three new limited editions of the Perpetual Moon 41.5 in June 2026, collectively titled “Colours of the Moon.” Each of the three references is built around a stainless steel case measuring 41.5mm in diameter and 11.67mm thick, and each is limited to 18 pieces. The collection is powered by the in-house calibre A&S1512, a hand-wound movement with a 90-hour power reserve operating at 21,600 vibrations per hour.
Three References, Three Lunar Phenomena
The naming of each edition is grounded in specific astronomical events rather than abstract colour association. The Blue Moon references the rare occurrence of a second full moon within a single season, and the atmospheric conditions that can cast the moon in cool blue tones. The Golden Moon draws from the warm amber appearance of the moon when seen near the horizon. The Red Moon corresponds to the reddish hue produced during a total lunar eclipse—commonly called a Blood Moon. Each reference translates its source phenomenon directly into material and colour choices across the dial.
Dial Architecture: The Moon as Primary Element
What distinguishes the Perpetual Moon’s design logic from most moon-phase watches is the scale and placement of the lunar display. The moon disc occupies much of the upper half of the dial, making it the dominant visual element rather than a subsidiary complication tucked into a subdial. This is not a conventional layout with a moon-phase aperture added to a time-display dial; the time display is arranged around the astronomical subject.
The moon disc itself is rendered in coloured mother-of-pearl—blue, gold, or red depending on the reference—and the surrounding night sky is also mother-of-pearl, treated through a Physical Vapour Deposition process to achieve black, blue, or green coloration. PVD on mother-of-pearl is a technically considered choice: the process adds colour saturation while preserving the organic material’s natural iridescence and depth, qualities that a painted or lacquered surface would not replicate. The result is a dial where both the moon and the sky it inhabits share the same material origin but are differentiated by colour and finish.
Super-LumiNova is applied beneath the moon disc, so the display glows softly in low light. The constellations Cassiopeia and Ursa Major are hand-painted onto the dial in luminescent material, completing the astronomical scene. These are not decorative flourishes applied after the fact; they are part of a coherent compositional scheme in which the entire dial surface functions as a single image.
Case and Crystal
The choice of stainless steel for this collection is a deliberate departure. Earlier Perpetual Moon references have appeared in precious metals, and the move to steel shifts the character of the watch without altering its fundamental design proposition. The polished case finish allows the material to read as clean and contemporary rather than understated. A domed sapphire crystal with double anti-reflective coating sits over the dial, and a sapphire caseback provides a view of the movement. Water resistance is rated to 30 metres.
At 11.67mm thick, the case is relatively slim for a watch carrying this level of dial construction and a 90-hour hand-wound movement. That proportion matters for daily wearability and also for how the watch sits on the wrist—a thicker case would shift the visual weight of the oversized moon display from elegant to imposing.
The Movement
Calibre A&S1512 measures 34mm by 5.35mm and carries 27 jewels. Its decoration follows established fine watchmaking conventions: radiating Côtes de Genève, polished bevels, circular graining, and blued screws. The movement also incorporates a secondary moon-phase indication on the caseback, which serves a functional purpose—it allows precise adjustment of the complication without disturbing the dial-side display. The moon-phase mechanism is engineered to require correction only after many years of continuous operation, a standard the brand has maintained across the Perpetual Moon line.
Finishing and Strap
Each reference is paired with an alligator leather strap matched to the dial colourway, closed with a stainless steel pin buckle. The strap coordination reinforces the edition-specific identity of each piece without requiring additional hardware changes.
- Blue Moon: Blue PVD mother-of-pearl sky, blue mother-of-pearl moon disc, reference 1GLBS.M03A.C263S
- Golden Moon: Black PVD mother-of-pearl sky, gold mother-of-pearl moon disc, reference 1GLBS.M02A.C672S
- Red Moon: Green PVD mother-of-pearl sky, red mother-of-pearl moon disc, reference 1GLBS.M01A.C1242S
Each version is produced in a series of 18 pieces. Given the hand-painted constellation work, the PVD-treated mother-of-pearl surfaces, and the movement finishing involved, that production figure is consistent with what the dial construction realistically demands.
