Launched at Baselworld 2013, the HM Perpetual Moon from Arnold & Son is one of the largest moon phase displays available today, with a moon phase disc of 29 mm.

Today is the date of the “Supermoon”, when the moon appears larger than normal, thanks to it being closest to the Earth during its elliptical orbit. In horology the HM Perpetual Moon from Arnold & Son is a contender for the wristwatch equivalent. A simple, but somewhat romantic, timepiece, the HM Perpetual Moon has the hours and minutes, and also a moon phase in grand detail and scale.  The watch case is 42 mm in diameter, but the moon phase disc is 29 mm and the moon itself is 11.2 mm, taking up half the dial. It depicts the moon in realistic detail, craters and all. The moon itself is cast from a hand-engraved die and then inserted onto the moon phase disc.

Set via a pusher in the case, the moon phase is mirrored by another moon phase display on the movement. This has an easy to read graduated dial for more accurate setting of the moon phase. Like most moon phase watches, this is accurate to a day in 122.5 years.

Inside is the A&S1512 manual wind calibre, with double barrels and an 80 hour power reserve. It was developed and manufactured by movement specialist La Joux-Perret, the sister company of Arnold & Son, both of which are now owned by Citizen.

Pictured above is the HM Perpetual Moon Elegant in rose gold with a brilliant blue lacquered dial that is extremely striking, and a retail price of SFr26,200. More restrained is the Classic model (shown below), also in rose gold but with an eggshell dial; this retails for SFr25,520. Additionally, a steel version with a black dial, the HM Perpetual Moon Modern, is also available with a retail price of SFr14,000. All prices exclude taxes. – SJX

HM Perpetual Moon Classic

HM Perpetual Moon Elegant