Audemars Piguet: Royal Oak Perpetual Calendar Openworked “150th Anniversary”

In 2025, Audemars Piguet celebrates its 150th anniversary, a long history during which the brand has distinguished itself with astronomical complications since 1875 with the first pocket watches of the two founders, Jules Louis Audemars and Edward Auguste Piguet. Today, to celebrate this important anniversary, the Manufacture presents the new Royal Oak Perpetual Calendar Openworked “150th Anniversary” limited edition. The last reference to house Calibre 5135, the movement that has powered Audemars Piguet’s 41 mm openworked perpetual calendars for almost a decade.

To bring past and present in conversation, the design codes of this limited edition’s are inspired by a historical openworked perpetual calendar pocket watch (ref. 25729) exhibited at the heart of the Musée Atelier Audemars Piguet. 

Fitted with a sapphire dial, the new Royal Oak Perpetual Calendar Openworked “150th Anniversary” gives pride of place to the openworked movement ticking within. The inner bezel and subdial surrounds reinterpret the contrasted aesthetic of the original pocket watch by featuring a rich blue hue that has been slightly darkened to harmonise with the deep colour of the matching bathtub hands in white gold, filled with luminescent material for optimal readability. In the same vein, the hour-markers are executed in a silver-grey shade and in a refined round shape to mirror the ones made of brilliant-cut diamonds on the historical timepiece. The white typeface used for the perpetual calendar’s numerical and alphabetical indications has also been revisited to lend the dial an elegant and vintage aesthetic. 

TITANIUM AND BULK METALLIC GLASS

For this 41 mm limited edition, the lightness of titanium is combined with the resistance of Bulk Metallic Glass (BMG).

Discovered in the 1960s, BMG is now used in applications as diverse as micro-electronics and golf. Produced in hundreds of different variations, this alloy shares several characteristics with other glasses when cooled rapidly, an essential step that prevents crystals from forming and freezes the material in a glassy state lending it strong, amorphous properties. Constantly experimenting with techniques, shapes and materials, Audemars Piguet has co-developed its own palladium-based BMG, composed of over 50% palladium, making it highly resistant to wear and corrosion with a glossy lustre. 

Used for the new limited edition’s bezel, caseback frame and bracelet studs, the BMG has been mirror-polished to reveal its unwavering glow, elegantly complementing the titanium case and bracelet links for a captivating play of light. Known to be lightweight and resistant to shock, the titanium presents a satin-brushed finish with polished chamfers enhancing this timepiece’s brilliance. 

THE MAJESTY OF THE MOON 

This openworked Perpetual Calendar reference’s moon-phase indication at 6 o’clock offers a different perspective on the passing of time. The phases of the lunar cycle are displayed on the dial by means of a disc decorated with a photographic representation of the Moon as seen from Earth. Based on a NASA photograph, this realistic image has been transferred onto the moon phase disc using metallisation on sapphire, paying tribute to the beauty of the celestial body. As it engages with the movement’s mechanism, the aperture on the dial presents the eight different phases of the 29.5-day lunar cycle, as seen from both sides of the equator. 

From our geocentric perspective, the Moon appears to change shape as it orbits the Earth. Although the lunar cycle is a global phenomenon, its eight phases appear in reverse whether the viewer is standing in the Northern or Southern hemisphere. This astronomical phenomenon is replicated in this limited edition’s perpetual calendar function which features two Moons to accommodate both perspectives. 

Selfwinding Calibre 5135, with 40 hours of power reserve, automatically takes into account the number of days in the month and correctly displays the prevailing date even in leap years. Assuming the watch is kept fully wound, the perpetual calendar will not require manual correction until 2100, at which point it will need to be adjusted to stay in line with the Gregorian calendar. 

Finally, this limited edition of 150 pieces is embellished with two additional design codes, specially created to celebrate the 150th anniversary of the Manufacture. On the dial side, the moon-phase indication at 6 o’clock harmoniously integrates an “Audemars Piguet” signature inspired by historical documents. The caseback frame includes two additional engravings: the “150” logo created in honour of the celebration, and the mention “1 of 150 pieces” in reference to the number of iterations produced.  (Price CHF 175,000)