Monochrome Watches
An online magazine dedicated to fine watches

The Arnold & Son Perpetual Moon 41.5 Platinum “Celestial Blue”

A beautiful new Moon rises at Arnold & Son.

| By Rebecca Doulton | 3 min read |

With two collections dedicated to our neighbouring satellite – Luna Magna and Perpetual Moon – it’s fair to say that the Moon exerts a powerful gravitational pull at Arnold & Son. In a departure from more conventional representations of the Moon portrayed in tiny dimensions constrained by tiny apertures, Arnold & Son’s astronomical moon phase complication is one of the largest on the market. The latest iteration of the Perpetual Moon returns in a sophisticated platinum case with a beautiful “Celestial Blue” dial.

Launched in 2013, Arnold & Son’s Perpetual Moon first appeared with a traditional guilloché dial with a large, realistic 11.20mm representation of the Moon, followed by a more spectacular model with not one but two moons, displaying the position of the Moon in both hemispheres. A few years later, the brand produced the lovely Perpetual Moon with an obsidian dial. Then, in 2022, it introduced a slightly smaller and redesigned 41.5mm case size with stunning “Stellar Ray” dials in salmon and royal blue. The latest Perpetual Moon sticks to the case dimensions of the “Stellar Ray” models – 41.5mm diameter x 11.30mm height – and shares the more refined lugs with bevelled edges and the slimmer bezel, giving precedence to the dial. Entirely polished, the elegant platinum case has a domed sapphire crystal over the dial and a sapphire caseback.

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To produce the beautiful deep-pleated “Stellar Ray” pattern on the dial, the surface is engraved with irregular rays. Not uniform, the width and depth of the rays vary, producing contrasting areas of shadow and light. The “Celestial Blue” tone is obtained with a PVD treatment and then coated with several layers of transparent lacquer. The protagonist of the watch is hosted in the large aperture in the top half of the dial. Set against a grained midnight-blue sky, the hand-painted, luminous constellations represent the Big Dipper and Cassiopeia. Since time immemorial, navigators have relied on these constellations to find their bearings at sea and are a reference to John Arnold’s historical marine chronometers.

Floating in the night sky is the realistically rendered mother-of-pearl Moon, complete with hand-painted shadows and a coating of Super-LumiNova, allowing it to emanate a mysterious glow in the dark. Rhodium-plated hour markers and hands relay the passing hours and minutes.

With a deviation of only one day every 122 years, the precision moon phase display has an adjustment system on the movement side. Traditional moon phases are usually adjusted by the crown, and it’s tricky to get the position of the moon just right. To counter this common problem, A&S has placed a second moon phase indicator with a precise scale and representations of the cycles on the caseback, allowing you to adjust the phases with extra precision.

The manual-winding in-house calibre A&S1512 beats at a frequency of 21,600vph and is fitted with a double barrel for a generous 90-hour power reserve. The finishings of the movement include radiating Côtes de Genève on the mainplate, polished and chamfered bridges, circular satin-finished wheels and blued and chamfered screws.

Availability & Price

Matching the colour scheme of the dial, the watch comes on a blue hand-stitched alligator leather strap with an 18k white gold pin buckle. The Perpetual Moon 41.5 Platinum “Celestial Blue” is a limited edition of 38 watches and retails for CHF 46,600 (incl. tax). For more information, please visit

1 response

  1. Wow. Beautiful dress watch. The dial shows Citizen’s DNA.

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