Audemars Piguet Royal Oak Perpetual Calendar Skeleton: Calibre 5135 150th Anniversary Edition
Aude Piguet unveils the Royal Oak Perpetual Calendar Skeleton “150th Anniversary” Limited Edition, marking the final appearance of the 5135 movement that has powered the brand’s 41 mm skeleton automatic perpetual calendar watches for nearly a decade.
The titanium and block metallic glass (BMG) case and bracelet of this watch contrast with the vintage aesthetic of the dial, inspired by a pocket watch in the Audemars Piguet Museum collection. Design elements introduced to commemorate the anniversary are also used in other models launched this year.
Leveraging the brand’s expertise in the field of perpetual calendars, Calibre 5134 was launched in 2015, adapting the perpetual calendar movement to a larger 41 mm case diameter while maintaining a slim profile of 4.5 mm.
Combining the ancient art of skeletonization with cutting-edge technology, Calibre 5135 was released in 2019 to power the Royal Oak Perpetual Calendar Skeleton in black ceramic (Ref. 26585CE), whose fine decoration can be admired from both the front and back of the watch.
Running at a frequency of 2.75 Hz (19,800 vibrations/hour) and boasting a 40-hour power reserve, the movement makes its final appearance in a limited edition to celebrate the brand’s 150 years of fine watchmaking history.
Its dial design is inspired by a historic skeletonized perpetual calendar pocket watch (Ref. 25729) exhibited at the heart of the Audemars Piguet Museum.
The contrasting aesthetic of the original pocket watch is reinterpreted around the inner ring and subdials, in a rich blue hue that is slightly deepened to harmonize with the dark color of the 18K white gold bathtub hands and filled with luminous material for optimal readability.
The hour markers are silver-grey and feature a refined circular design, echoing the hour markers made from brilliant-cut diamonds on classic timepieces. The white font used for the perpetual calendar’s numerical and letter indications has been redesigned for a more vintage aesthetic.
The moon phase display disc at 6 o’clock is adorned with a photograph of the moon as seen from Earth. The photograph is based on a NASA image and is transferred to the moon phase disc using a sapphire metallization process. As the mechanism advances, the aperture on the dial will display the eight phases of the 29.5-day lunar cycle, clearly visible from both the northern and southern hemispheres.
The self-winding 5135 movement is able to accurately calculate the length of the month and accurately display the date, including leap years. If fully wound, the perpetual calendar will remain accurate until the year 2100, when it will need to be manually adjusted to align with the Gregorian calendar.
The case of the reference 26585XT measures 41 mm x 9.9 mm and is made of titanium, with BMG used for the bezel, caseback frame and bracelet rivets.
Discovered in the 1960s, BMG was originally used in microelectronics and golf equipment. Due to its amorphous structure, BMG exhibits exceptional hardness, wear resistance and corrosion resistance. It also has a unique luster that distinguishes it from traditional metals.
For the first time, Audemars Piguet combined titanium with BMG (bulk metallic glass) to create the unique Royal Oak “Jumbo” ultra-thin watch (Ref. 15202XT), created exclusively for Only Watch 2021, and introduced palladium-based metallic glass to watchmaking. The material was subsequently used in the Royal Oak “Jumbo” watch (Ref. 16202XT).
The Royal Oak Perpetual Calendar Skeleton “150th Anniversary” watch (Model: 26585XT.OO.1220XT.01) incorporates Audemars Piguet’s 150th anniversary elements, including the signature in the moon phase display at 6 o’clock, inspired by historical documents, and the commemorative “150” logo and “1/150” engraved on the caseback frame.