An ethereal complication as the dial's crowning glory.

Chronometers made by the exceptional trailblazing watchmaker John Arnold were used by sailors and explorers. A moon-phase display is one thing you won't find on the watchmaker's historic creations, but that hasn't stopped the modern owners of the brand Arnold & Son from foregrounding the role of the Earth's satellite.

After all, the watch brand's main lunar collections have been hugely successful: Luna Magna and Perpetual Moon. Both of them boast large representations of the Moon but take different approaches.

Luna Magna brings together models with imposing lunar spheres at 6 o'clock (12 mm in diameter), while Perpetual Moon models display a flat yet realistic depiction of the Earth's satellite at 12 o'clock (the Moon is slightly more modest here at 11.2 mm).

Perpetual Moon models have been produced for over ten years now, and a wealth of versions have appeared in the collection since its debut in 2013, including a watch with two moons to depict phases in both hemispheres, and a variety of dial compositions.

Their dials have been decorated with guilloché patterns, and have used mother-of-pearl, obsidian and aventurine with mother-of-pearl fragments. Last year's Moon was framed with the fan-like Stellar Rays finish for the first time. A blue edition with this decoration was used for the watch in red gold, and a salmon edition was housed in platinum.

For 2023, the brand Arnold & Son decided to combine the platinum case with the blue "fan" dial featuring a mother-of-pearl Moon on the Perpetual Moon 41.5 Platinum “Celestial Blue”. The case size remains the same: 41.5 mm × 11.30 mm.

The movement responsible for keeping the Moon on the dial in sync with the movements of the Moon in the sky is the manually wound Arnold & Son A&S1512, which boasts an impressive 90-hour power reserve.

The specs for the moon-phase display's precision are no less impressive, with a deviation of just one day every 122 years. Few will be lucky enough to enjoy these specs: availability of the Perpetual Moon 41.5 Platinum “Celestial Blue” is limited to just 38 pieces.