Swiss Haute Horlogerie manufacturer Audemars Piguet is pleased to reveal the Royal Oak Perpetual Calendar Openworked “150th Anniversary” limited edition, reflecting the brand’s rich legacy in design, material and technical exploration. This timepiece is the last to be equipped with Calibre 5135 and gracefully bids farewell to the movement that has powered the Manufacture’s 41 mm openworked selfwinding perpetual calendar wristwatches for nearly a decade. Enhancing its timeless appeal, this model’s high-tech combination of titanium and Bulk Metallic Glass (BMG) on the case and bracelet creates a sophisticated contrast with the dial’s vintage aesthetic inspired by a pocket watch exhibited in the Musée Atelier Audemars Piguet (reference 25729). This elegant limited edition of 150 pieces is adorned with design codes developed specifically for the anniversary that extend to other pieces of this year’s offering, celebrating the Manufacture’s enduring commitment to watchmaking tradition and innovation.
A Final Tribute To Calibre 5135
This year, the brand honours its solid foundations while embracing innovation for the future. The Royal Oak Perpetual Calendar Openworked “150th Anniversary” is the last reference to house Calibre 5135, the movement that has powered Audemars Piguet’s 41 mm openworked perpetual calendars for almost a decade, closing down the curtain on a story that began in 1978 with the birth of its historic predecessor.
In the dawn of the 1970s, at the height of the quartz crisis, Audemars Piguet released the thinnest selfwinding perpetual calendar wristwatch of its time equipped with the ground-breaking Calibre 2120/2800. Conceived in secret by three dedicated watchmakers, this perpetual calendar movement set new industry standards, ushering a significant era of growth for the company. Over the next 18 years, the Manufacture produced, cased and sold more than 7,000 movements, reviving other classic complications along the way, including the openworked chronograph (1980), the first selfwinding tourbillon (1986), the minute repeater (1992) and the Grande Complication combination (1996). In 1984, Calibre 2120/2800 made its debuts in the Royal Oak collection (Model 5554), and an openworked version was introduced two years later (Model 25636). Although the production of perpetual calendar wristwatches was well underway, the company continued to create avant-garde and classical pocket watches with this complication too.
Building on its predecessor’s legacy, Calibre 5134 was launched in 2015, adapting the perpetual calendar movement to a larger 41 mm case diameter while maintaining a thin 4.5-mm profile. It was housed in a new Royal Oak model with a dynamic aesthetic (ref. 26574), bringing renewed attention to a complication whose popularity had been in decline since 1989. This revival was confirmed in 2017 with the launch of a black ceramic animation causing a sensation (ref. 26579CE), which laid the foundations for many creative innovations in the perpetual calendar line.
Combining the ancient art of openworking with cutting-edge technology, Calibre 5135 was released in 2019 to power the Royal Oak Perpetual Calendar Openworked in black ceramic (ref. 26585CE), revealing the movement’s refined decorations from both the front and the back of the watch. This sophisticated calibre has since then equipped various iterations, including an 18-carat white gold model set with 962 diamonds (ref. 26625BC) and a collaboration with Cactus Jack (ref. 26585CM) in 2023, before exploring new creative possibilities with Frosted Gold (ref. 26585BC) last year. After nearly a decade, this movement takes its final bow in a limited edition dedicated to celebrating the brand’s 150 years of fine watchmaking.
A Dial Nodding To The Past
To bring past and present in conversation, the design codes of this limited edition’s dial 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 18-carat 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.
High-Tech Materials For Enhanced Ergonomics
For this 41 mm limited edition, the lightness of titanium is combined with the resistance of Bulk Metallic Glass (BMG), pushing material exploration and creativity further.
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. The Manufacture first coupled titanium with BMG for the one-of-a-kind Royal Oak “Jumbo” Extra-Thin timepiece (ref. 15202XT) created for Only Watch in 2021, which also inaugurated the use of palladium-based metallic glass in watchmaking. BMG was further introduced to the Royal Oak’s “Jumbo” (ref. 16202XT) line two years later, before adorning a Royal Oak Perpetual Calendar (ref. 26585XT) in 2024.
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[1], 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 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[2].
Celebrating The Anniversary With Special Decorations
This limited edition of 150 pieces is one of the references enhanced by subtle design codes specifically created to celebrate the Manufacture’s 150th anniversary. 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.
[1] Metallisation on sapphire consists of applying a thin layer of metal onto a sapphire using Physical Vapour Deposition (PVD). Achieved with extreme precision in a vacuum environment, this process ensures a uniform and controlled adhesion to the glass, allowing the creation of various graphic elements including logos, motifs and designs.
[2] The Gregorian calendar omits three leap years every 400 years to remain in line with solar time. This is achieved by omitting February 29 in the century years which are divisible by 100, but not by 400. As a result, 2100 will not be a leap year and perpetual calendar mechanisms will have to be moved forward by one day. This correction does not apply to the week indication.
Audemars Piguet Royal Oak Perpetual Calendar “150th Anniversary” Openworked / 41 mm
Ref. 26585XT.OO.1220XT.01 Limited edition of 150 pieces – UVP/€ 221.100 (daily rate)
Functions
- Perpetual calendar with week indication, day, date, astronomical moon, month, leap year indication, hours and minutes.
Movement Specifications
- Selfwinding Calibre 5135
- Total diameter 29 mm (12 ¾ lignes)
- Total thickness 4.5 mm
- Number of parts 374
- Number of jewels 38
- Minimum power reserve guaranteed 40 h
- Frequency of balance wheel 2.75 Hz (19,800 vibrations/hour)
Case
- Titanium case, BMG bezel and caseback frame, glare-proofed sapphire crystal and caseback, screw-locked titanium crown, water-resistant to 20 m.
- Case thickness: 9.9 mm
Dial
- Sapphire dial, blue brass inner bezel, round hour-markers and blue bathtub hour and minute hands in 18-carat white gold with luminescent material.
Bracelet
- Titanium bracelet links with BMG studs and a three-blade titanium folding clasp.
About Audemars Piguet
Audemars Piguet is the oldest fine watchmaking manufacturer still in the hands of its founding families (Audemars and Piguet). Based in Le Brassus since 1875, the company has nurtured generations of talented craftspeople who have continuously developed new skills and techniques, broadening their savoir-faire to set rule-breaking trends. In the Vallée de Joux, at the heart of the Swiss Jura, Audemars Piguet has created numerous masterpieces, testament to the Manufacture’s ancestral savoir-faire and forward-thinking spirit. By pushing the boundaries of what is possible and building bridges between different creative worlds, Audemars Piguet has been able to explore new horizons and build an inspired community. Seek Beyond. — www.audemarspiguet.com