The Hourstriker Verdict
To celebrate its 150th anniversary, Audemars Piguet has just unveiled its 150 Heritage Ultra-complication Universal Calendar. This 50 mm platinum pocket watch boasts an unbelievable 1,099 part movement in the manual wound Calibre 1150 with 47 functions. Along with the Neo Frame Jumping Hour watch, AP has really put out some very unexpected releases to kick of 2026, something we're huge fans of.
— Peter, Editor-in-Chief
Audemars Piguet has marked the occasion of its 150th anniversary with the introduction of the 150 Heritage Ultra-complication Universal Calendar, a pocket watch that effectively miniaturizes a centuries-spanning history of astronomical observation into a 50mm platinum chassis. Designated Reference 75150PT.OO.01, this timepiece represents a significant divergence from the manufacture's recent focus on wrist-worn ultra-complications, instead returning to the pocket watch format to accommodate the newly developed Calibre 1150. This manual-winding movement is a direct evolution of the Calibre 1000 found in the Code 11.59 Ultra-Complication Universelle (RD#4), yet it has been extensively re-engineered to function within the vertical orientation and specific ergonomic requirements of a pocket watch. The timepiece aggregates 47 distinct functions, including 30 complications, ranging from a Grande Sonnerie and minute repeater to a split-seconds flyback chronograph and a semi-Gregorian perpetual calendar.
The release serves as a technical bridge between the manufacture's archival "super-watches"—specifically the 1899 L’Universelle and the 1921 La Grosse Pièce—and its modern research and development lineage, notably the RD#1, RD#2, and RD#3 projects. While the movement architecture borrows heavily from the RD#4, the translation to a pocket watch required a complete restructuring of the activation mechanisms. The crown-pushers and correctors have been repositioned and redesigned to facilitate operation in the palm rather than on the wrist, with specific attention paid to the tactile resistance and travel of the pushers. The device is not merely a horological instrument but a mechanical calculator of significant density, boasting 1,099 components within a movement thickness of just 8.9mm, encased in a total profile of 23.4mm. It stands as one of the few modern attempts to synthesize a high-frequency 3Hz balance with the immense energy demands of a Grande Sonnerie and a complex astronomical display.
Courtesy of Audemars Piguet
The Case and Dial Architecture
The exterior chassis of the 150 Heritage is machined from platinum, a material historically chosen for high complications due to its density and corrosion resistance, though it poses significant challenges regarding acoustic transmission. To counteract the natural dampening properties of platinum, Audemars Piguet has integrated its proprietary Supersonnerie technology. This involves a dedicated soundboard construction within the caseback that decouples the chiming gongs from the main case material, allowing for a resonance quality and volume typically unachievable in platinum housings. The case measures 50mm in diameter and is finished with intricate hand-engraving that covers the entirety of the case band and bezel. This engraving is not merely decorative texturing but a deliberate application of commemorative motifs and 150-year anniversary emblems, executed with a burin to varying depths to create a tactile relief that interacts with ambient light.
Beneath the glare-proofed sapphire crystal lies a dial composed of blue translucent Grand Feu enamel. This traditional enameling technique involves applying oxide powders to a metal substrate—in this instance, 18-carat white gold—and firing them at extremely high temperatures (approximately 800°C) repeatedly to achieve vitrification. The translucency of the enamel reveals the underlying hand-engraved guilloché patterns, specifically "star trails" that radiate across the surface, reinforcing the astronomical theme of the complication. The timekeeping indications are provided by 18-carat pink gold hands which contrast sharply against the blue substrate for legibility, while the chronograph split-seconds hand is rendered in white gold to distinguish it during timing operations. The subdials feature a tone-on-tone aesthetic with silver-grey threads, ensuring that the density of information—day, date, month, moon phase, and chronograph counters—does not compromise the immediate readability of the primary time.
Courtesy of Audemars Piguet
Calibre 1150 and Complications
The mechanical heart of the 150 Heritage is the Calibre 1150, a hand-wound movement that effectively consolidates the technical breakthroughs of the last decade of Audemars Piguet’s R&D. The movement operates at a frequency of 3 Hz (21,600 vibrations/hour) and provides a guaranteed power reserve of 60 hours, a notable figure given the parasitic drag inherent in driving a split-seconds chronograph and a Grande Sonnerie. The acoustic mechanism features a carillon with three gongs and hammers, capable of striking the hours and quarters in passing (Grande Sonnerie), hours only (Petite Sonnerie), or on demand via the minute repeater. The repeater activation has been re-engineered from a traditional slide to a pull-function on the crown-pusher at 2 o’clock, a system designed to prevent accidental triggering while the watch is pocketed. Furthermore, the "silent" regulator, a patented innovation from the RD#1, eliminates the background buzzing noise typically associated with the governor in traditional repeater movements.
The chronograph function utilizes a flyback mechanism paired with a split-seconds (rattrapante) complication, controlled by a vertical clutch system to eliminate the "jump" often seen in horizontal clutch engagement. The split-seconds function allows for the measurement of intermediate time intervals and is operated via a pusher integrated into the crown. The movement also houses a flying tourbillon at the 6 o'clock position, which rotates the escapement and balance wheel to average out positional errors caused by gravity—a complication that is theoretically more effective in a pocket watch, which spends the majority of its time in a single vertical position, than in a wristwatch. The semi-Gregorian perpetual calendar mechanism advances the date, day, month, and year automatically, accounting for month lengths and leap years. Crucially, it is programmed to require no manual correction until the year 2100, at which point the suppression of the leap year in the Gregorian calendar will necessitate a manual adjustment.
Courtesy of Audemars Piguet
The Universal Calendar
Accessible via a hinged "hunter" style caseback, the Universal Calendar is a distinct mechanical entity separate from the dial-side indications. This mechanism is a dedicated calculator for lunisolar cycles, offering a panoramic display of astronomical phenomena and their correlation to civil and religious timekeeping systems. While traditional perpetual calendars are bound to the Gregorian system, the Universal Calendar acknowledges the plurality of global timekeeping by indicating cultural celebrations derived from solar, lunar, and lunisolar logic. These include events such as Easter, Passover (Pesach), Chinese New Year, and Ramadan. The mechanism displays these floating holidays by mechanically calculating the interaction between the solar year and the lunar cycles.
The display is organized around a central focus, utilizing concentric rings to indicate the month, the week, and the position within the Metonic cycle—a 19-year period after which the phases of the Moon recur on the same days of the solar year. The mechanism is capable of projecting these cycles from the year 1900 through 2099. Unlike the main movement which requires winding, the Universal Calendar is an independent module corrected and set via a bidirectional wheel in the caseback. A single full rotation of this wheel updates the calendar through an entire Metonic cycle. The display plate is crafted from 18-carat white gold and features the same blue translucent enamel and star trail engraving as the obverse dial, ensuring aesthetic continuity between the timekeeping and astronomical faces of the watch.
Courtesy of Audemars Piguet
The Chain and Production Limitations
To secure the timepiece, Audemars Piguet has produced a hand-crafted platinum chain, measuring approximately 40 centimeters in length. The fabrication of a platinum chain presents specific metallurgical challenges; platinum is significantly denser and less malleable than gold, causing higher tool wear and requiring more force to shape links. Each link is hand-assembled and polished to match the finishing of the main case. The chain is fitted with two spring ring clasps, designed to offer secure attachment to a waistcoat or trousers, reflecting the functional intent of the object despite its high-value status. The use of platinum for both the case and chain significantly contributes to the substantial heft of the object, distinguishing it from lighter titanium or gold alternatives.
The Audemars Piguet 150 Heritage Ultra-complication Universal Calendar is an extremely limited production run. Only two examples have been manufactured in platinum, referencing the exclusivity of the brand's early 20th-century commissions. The manufacture has indicated that eight additional variations in 18-carat white gold will be produced in the near future, though the platinum "Launch Edition" remains a distinct entity. Pricing for the Reference 75150PT.OO.01 is strictly on request, reflecting the bespoke nature of the production and the labor hours involved in the assembly and regulation of the 1,099 components.
Courtesy of Audemars Piguet
Technical Specifications
Case: 50mm diameter, 23.4mm thickness, Platinum 950, hand-engraved, glare-proofed sapphire crystal, Supersonnerie soundboard caseback.
Movement: Calibre 1150, Hand-Wound, 34.3mm diameter, 8.9mm thickness, 1,099 parts, 81 jewels, 3 Hz (21,600 vph) frequency, 60-hour power reserve.
Dial: Blue translucent Grand Feu enamel on 18-carat white gold, hand-engraved Roman numerals, 18-carat pink gold hands, white gold split-seconds hand.
Functions: Grande and Petite Sonnerie, Minute Repeater, Flying Tourbillon, Split-Seconds Flyback Chronograph, Semi-Gregorian Perpetual Calendar, Universal Calendar (caseback).
Chain: Hand-made platinum chain (~40 cm) with two spring ring clasps.
Price: Price on Request.
Reference Number: 75150PT.OO.01
Notes: Limited to 2 pieces in platinum; 8 pieces in white gold to follow. Universal Calendar mechanism independent of base movement.