In true Arnold & Son tradition, the brand has released one of the most alluring and precise moonphase watches. The HM Perpetual Moon, with one of the biggest moonphase apertures on the market, rightfully joins the Arnold & Son Royal Collection. The Royal Collection is inspired by the timepieces created in the early part of John Arnold's life, and pay tribute to the watches he produced for King George III and members of the royal court. The timepieces in the Royal Collection demonstrate the brand's prowess in traditional watchmaking and classical decorative arts.

The sophisticated HM Perpetual Moon is, indeed, a superb example of Arnold & Son's technical and artistic excellence. From the inside out, this new timepiece - with richguillochédials and three-dimensional big moon - surprises and delights. The 42 mm case is created in either 18-carat red gold or in stainless steel and houses the exclusive Arnold & Son mechanical hand-wound movement, the 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 to yield 90 hours of power reserve.

The exceptional perpetual moonphase indication of this watch is a marvel in many ways. From the aesthetic side, the 29 mm moonphase disc, which runs from 10 to 2 o'clock on the dial, reveals one of the largest moons on the market - with a diameter of 11.2 mm for the moon alone. Additionally, this large moon is one of the most visually stunning recreations of the moon because it is a three-dimensional sculptured moon that was first hand-engraved and then duplicated for the series. The sculptured moon is then inserted into the disc.

From the technical side, in addition to the HM Perpetual Moon being so precise, it is also an intriguing complication in that it is not simply a module added to the movement, but, in fact, is fully integrated into the calibre. The watch also has a unique easy-to-set feature thanks to the ingenious addition of a second moon indication installed at the back of the movement. This second moon display, visible via a transparent case back, features a graduated dial and a pointer hand that allows for a more exact setting.

The multiple technological advancements in the calibre make this timepiece truly outstanding. To further underscore that, the entire rhodium treated nickel-silver movement features hand finishing indicative of the finest Haute Horlogerie timepieces, including manually chamfered bridges with polished edges, fine circular graining with polished edges and Côtes de Genève rayonnantes, and blued screws. The timepiece naturally features an anti-reflective sapphire crystal and case back to view the meticulous details.

Taking the HM Perpetual Moon to higher heights, Arnold & Son offers three very distinct versions for today's discerning clientele. The Elegant model is created in 18-carat red gold with an incredible blue guilloché dial in a stylized sunray pattern, blue guilloché moon disc with golden stars and the hand-engraved moon. The Classic model, also crafted in 18-carat red gold, features a cream-colored dial with a blue guilloché moon disc with golden stars and the hand-engraved moon. The Modern model is created in stainless steel and features a black guilloché dial with black guilloché moon disc with the hand-engraved moon.  Each timepiece is accented with a hand-stitched alligator strap. In all, the HM Perpetual Moon is a beguiling work of technical mastery and fine art.