Perpetual Moon 41.5 Platinum LTD 28 celestial-blue

A Blue Moon in Platinum

At the crossroads of astronomical precision and refined Swiss craftsmanship, Arnold & Son unveils the Perpetual Moon 41.5 Platinum “Celestial Blue”—a timepiece that transforms the moon-phase complication into a luminous composition of serenity, depth, and celestial poetry.

Housed in a 41.5mm case crafted from Pt950 platinum, this limited edition of 28 pieces expresses the radiance of the night through a delicate palette of pale blue, midnight blue, and the cool brilliance of platinum. With its generous dial opening, refined case proportions, and immense moon display, the Perpetual Moon 41.5 Platinum draws the eye toward the sky and places the lunar spectacle at the heart of the composition.

Astronomical Precision: The A&S1512 Calibre

At the heart of the Perpetual Moon 41.5 Platinum “Celestial Blue” beats the Calibre A&S1512, a hand-wound Manufacture movement entirely developed, manufactured, decorated, assembled, adjusted, and cased by Arnold & Son in La Chaux-de-Fonds. Conceived to track the lunar cycle with exceptional accuracy, this calibre reflects the Maison’s deep connection to astronomy and marine chronometry.

Operating at a frequency of 3 Hz and offering a 90-hour power reserve, the A&S1512 calibre combines technical reliability with celestial refinement. On the caseback, a secondary moon-phase indicator allows the display to be adjusted quickly and precisely, reinforcing the watch’s role as both an elegant timepiece and a true astronomical instrument.

A Moon of Mother-of-Pearl

The Perpetual Moon 41.5 Platinum “Celestial Blue” is defined by its large white mother-of-pearl moon, realistically rendered with hand-painted shadows and enhanced with Super-LumiNova. Set against a grained sky with midnight-blue PVD treatment, the moon appears suspended in a deep nocturnal landscape, revealing a new luminous presence after dark.

The display follows the true duration of a complete lunar cycle: 29 days, 12 hours, 44 minutes, and 2.8 seconds. Thanks to Arnold & Son’s meticulous calculation, the moon phase would require only a one-day correction after 122 years, provided the watch remains regularly wound.

A Celestial-Blue Dial: Radiance, Depth and Constellations

The identity of the Perpetual Moon 41.5 Platinum “Celestial Blue” is expressed through its celestial-blue dial, animated by Arnold & Son’s “Stellar Rays” decor. Irregular engraved rays of varying depths and widths create a refined shimmer, while several layers of transparent lacquer accentuate the play of light and bring depth to the composition.

Around the moon, the Big Dipper and Cassiopeia constellations are hand-painted and coated with luminescent material. Chosen as references to John Arnold’s history as a maker of naval chronometers, these guiding stars recall the celestial points that have helped navigators orient themselves since time immemorial.