A few years ago Arnold & Son released what is arguably one of the most beautiful moon-phases on the market today; the HM Perpetual Moon. Given the incredible attractiveness of this timepiece logic dictates that the only way to possibly improve on its aesthetic appeal would be to duplicate its defining feature, which is exactly what they have done. Introducing the Arnold & Son HM Double Hemisphere Perpetual Moon. That’s right, double moon-phases.

The HM Double Hemisphere Perpetual Moon

A double-moon phase is a bold undertaking under any circumstances but especially so when your watch features one of the largest moon-phase displays on the market. Fortunately, as it always seem to do in these matters, Arnold & Son has come through this test with flying colors.

Rather than trying to dramatically alter the design of the original – which would have been mortifying to say the least – the brand has chosen to simply mirror the success of its first design on the bottom half of the dial. This looks exactly as it sounds; the first aperture displays the moon phase as seen in the northern hemisphere, whilst the second aperture simultaneously displays a mirror image of this same moon phase but as seen in the southern hemisphere. The only difference of course is the constellations shown on each disc.

Arnold & Son HM Double Hemisphere Perpetual Moon

So how big does a moon phase need to be to qualify as one of the biggest on the market? Well in full each moon phase disc on the HM Double Hemisphere Perpetual Moon, which run from 10 to 2 and 4 to 8 o’clock respectively, measure 29 mm. What is really impressive though is the moons themselves, each of which has a diameter of 11.20 mm. The three-dimensional sculptured moons were first hand-engraved and then duplicated for the series, giving them that hyper realistic finish.

Accentuating all of this of course is that gorgeous blue guilloché dial complete with stylized sunray pattern that does a mighty fine job of representing the night sky and basically causes me to drool every time I look at it. Perhaps best of all though is the fact that the HM Double Hemisphere Perpetual Moon is still presented in the same, extremely wearable, 42mm case made from 18-karat red gold.

Arnold & Son HM Double Hemisphere Perpetual Moon

Anyone who knows anything about Arnold & Son though will tell you the brand is about far more than just pretty dials and carefully sculpted moons – there has to be substance to the form and the HM Double Hemisphere Perpetual Moon does not disappoint. Powered by the hand-wound, calibre A&S1512, the 27 jewel calibre offers one of the most accurate moon phases on the market, with only one day’s deviation every 122 years – at which point a single push on the corrector will keep it in sync for another 122 years. The calibre is also equipped with a double barrel, offering a healthy 90 hours of power in reserve.

It’s also worth noting that the moon-phase display on the HM Double Hemisphere Perpetual Moon is not a module bolted on top of the movement but is rather fully integrated into the calibre. To make the most of this a third moon phase indication – visible via the transparent case back- has been installed at the back of the movement to allow for a unique and easy way to set the dual moon phases on the front dial.  This third moon display features a graduated dial and a pointer hand that allows for a more exact setting.

Arnold & Son HM Double Hemisphere Perpetual Moon

Finally, as you’d expect from Arnold & Son, the entire rhodium treated nickel-silver movement features a high-degree of hand finishing, including manually chamfered bridges with polished edges, fine circular graining with polished edges and Côtes de Genève rayonnantes, as well as blued screws of course. Completing the look is a hand-stitched alligator strap.

Pricing is set at a very reasonable US$30,500 and given that Baselworld is next month stay tuned for a hands-on look at the new HM Double Hemisphere Perpetual Moon as well as all the other new releases from Arnold & Son.

Tom Mulraney
Tom Mulraney
Founder & Editor
Tom likes to write about luxury watches. So much so, that he created The Watch Lounge just so he would have an outlet for his passion. Together with his team, he is dedicated to bringing you original, entertaining (and maybe even a little educational) luxury watch and lifestyle content.

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