For the first time, the 41 mm case and bracelet of the Royal Oak Perpetual Calendar are made entirely of blue ceramic in this reference 26579CS. Lightweight and resistant to wear and scratches, ceramic enhances the subtlety of this timepiece, which features a thickness of 9.5 mm.
Ceramics require precise workmanship and meticulous decorations performed by hand to meet the Manufacture's rigorous quality standards. Zirconium oxide powder (ZrO₂), modified to achieve blue pigmentation when fired, is mixed with a specific binder before being transformed into ceramics through a complex industrial process involving several high-precision processing steps. The exact composition of the ceramic remains a secret from its manufacturers. The components achieve their final color only after being sintered at more than 1,400°C. Achieving a homogeneous color poses an additional challenge, as the final shade is strictly dependent on the sintering temperature, which does not allow for variations.
Le Brassus artisans have finished each ceramic component with the same meticulous attention to detail reserved for precious metals: the alternation between satin finish and polished bevels, a distinctive feature of the Manufacture, has been applied by hand with extreme care. The result is a refined play of light that enhances both the ceramic and the faceted architecture of the Royal Oak.
A COMPLICATION WITH ELECTRIC BLUE HUES
The Manufacture's artisans harmonized the blue tones of the "Grande Tapisserie" dial , counters and inner chapter ring, obtained by physical vapor deposition (PVD), with the blue ceramic case and bracelet, giving the Royal Oak Perpetual Calendar a contemporary monochromatic aesthetic. Applied 18K white gold indexes and faceted hands, filled with luminescent material for optimal visibility in the dark, create a luminous contrast.
With the three calendar counters and moon phase aperture harmoniously distributed on the dial, the watch provides perfect aesthetic balance and excellent legibility of the hours, minutes, day, date, week, month, astronomical moon, and leap year indication.
AN ELEGANT PERPETUAL CALENDAR MOVEMENT
This new model is equipped with the automatic caliber 5134, a testament to the Manufacture's expertise in classic complications. This mechanism automatically takes into account the number of days in each month and correctly displays the date even in leap years. If the watch is kept wound, no manual intervention will be necessary until 2100 to stay in line with the Gregorian calendar (In the Gregorian calendar, the February 29 leap years are omitted every 100 years - e.g., 2100, 2200, 2300 - with the exception of secular years divisible by 400 - e.g., 2000, 2400, 2800 - to maintain alignment with solar time. As a result, 2100 will not be a leap year and perpetual calendar mechanisms will have to be advanced by one day).
Launched in 2015, this movement only 4.3 mm thick required a redesign of many components, including the 22-karat gold pierced oscillating weight. The bulkiest part of the rotor was positioned along the outer edge, recessed in a channel surrounding the movement, thus reducing the overall height. In addition, the choice of a suspended barrel helped contain the thickness of the movement.
The sapphire case back allows visitors to admire the traditional Haute Horlogerie decorations applied to Caliber 5134: Côtes de Genève, perlage, soleil finish, and polished bevels.
A HISTORY OF EXCELLENCE
Astronomical watches have deep roots in the watchmaking history of the Vallée de Joux, where craftsmen have always drawn inspiration from the region's crystalline night sky. Audemars Piguet's tradition of astronomical complications dates back to masterpieces made by the two founders during their formative years, completed around 1875. Jules Louis Audemars' watch(Audemars Piguet Heritage Collection, Inv. 8), which combined a perpetual calendar with a minute repeater and a rare independent deadbeat seconds function, underwent several evolutions over the next two decades. However, in the company's first two decades, calendar complications accounted for less than 10 percent of total production.
Audemars Piguet's first full calendar wristwatch was put into production in 1921 and sold three years later to the famous retailer Gübelin. Between 1921 and 1970, the Manufacture produced only 188 full calendar wristwatches, a small percentage of total production. In 1955, the Manufacture launched the first wristwatch with perpetual calendar and leap year indication, produced in only 9 pieces between 1955 and 1957.
Another record was set in 1978, during the quartz crisis, with the launch of the world's thinnest automatic perpetual calendar wristwatch. Created in secret by three passionate watchmakers, this extraordinary timepiece achieved a record thickness of 3.95 mm through the use of the ultra-thin caliber 2120, introduced in 1967 as a base. Over the next 15 years, Audemars Piguet produced 7,219 perpetual calendar watches equipped with this caliber. The success of the caliber 2120/2800 marked a new era for the Maison, encouraging the return of classic complications. This movement was adopted for many Royal Oak Perpetual Calendar models starting in 1984.
In 2015, Caliber 5134 adapted the perpetual calendar movement to a 41 mm Royal Oak case(Model 26574), maintaining a slim 4.3 mm profile. This caliber has equipped many of the Manufacture's perpetual calendar models since its launch.
In 2018, the Manufacture wrote a new chapter in the history of perpetual calendars with the 41mm Royal Oak Selfwinding Perpetual Calendar Ultra-Thin, known as RD#2, which became the thinnest automatic perpetual calendar wristwatch in the world at the time of its launch. With a total thickness of 6.3 mm, this timepiece houses Caliber 5133, a newly developed movement only 2.89 mm thick, marking the beginning of a new generation of astronomical watches.
Royal Oak Perpetual Calendar / 41 mm
26579CS.OO.1225CS.01
FEATURES
Perpetual calendar showing day, date, week, month, astronomical moon and leap year, hours and minutes.
CASH
Blue ceramic case with screw-down crown, anti-reflective sapphire crystal and titanium case back, water resistant to 20 m.
Case thickness: 9.5 mm
QUADRANT
Blue dial with Grande Tapisserie pattern, blue counters and inner minute track, white gold applied hour markers, and Royal Oak hands with luminescent coating.
BRACELET
Blue ceramic bracelet with titanium AP folding clasp.
MOVEMENT SPECIFICATIONS
Self-winding Caliber 5134
Total diameter: 29 mm (12¾ lignes)
Total thickness: 4.3 mm
Number of components: 374
Number of rubies: 38
Minimum guaranteed power reserve: 40 h
Balance frequency: 2.75 Hz (19,800 vibrations/hour)
