A. Lange & Söhne presents three of the most sophisticated watchmaking complications in a classic design with the 1815 Rattrapante Perpetual Calendar.
The rattrapante function of the 1815 rattrapante perpetual calendar represents one of the greatest horological challenges. In addition to the conventional functions of a chronograph, this sophisticated complication is capable of measuring intermediate times and comparative times as well as determining minimum and maximum values in the course of one minute. Since the balance wheel of the manufacture calibre L101.1 beats with six semi-oscillations per second, the stopped times can be recorded with an accuracy of one sixth of a second. High-precision readings are assured thanks to the additional graduation on the peripheral minute scale.
The precisely orchestrated proceedings within the movement can be observed through the sapphire-crystal caseback. The classic two-column wheel transmission is used to control the measurement of stopped and intermediate times. The upper surfaces of all moving parts are decorated with straight graining while the peripheral chamfers are polished. Only an experienced finisseur has the skill to polish the bevels to sharp and flat perfection.
As its name suggests, the complex and prescient mechanism ensures that the date, day of the week and month are correctly displayed ‒ every single day, during decades, even taking leap years into account. The calendar indications must only be corrected by one day but not until 1 March 2100; according to the rules of the Gregorian calendar, the leap year will then be skipped. The high-precision moon-phase display has also been programmed with the long term in mind. It so closely emulates the duration of the synodic orbit of the earth’s satellite that it would take 122.6 years for the display to be corrected by one day.
The manifold displays of the perpetual calendar and the rattrapante chronograph echo the classic aesthetics of earlier Lange pocket watches. The two pairs of combined calendar indications are arranged at 3 and 9 o’clock. The left subsidiary dial shows the date and day of the week, the right the month and leap year. Sharing an auxiliary dial with the subsidiary seconds at 6 o’clock, the moon-phase display provides an expressive colourful accent. The minute counter and power-reserve indicator are located at 12 o’clock.
Incorporating traditional design and engineering features, the manually wound movement L101.1 totals 631 individual parts. The mechanism of the perpetual calendar alone requires 211 components, a further 206 account for the rattrapante-chronograph mechanism. A screw balance, which is driven by the balance spring developed and manufactured in-house, ensures high rate stability. Lange-typical quality hallmarks such as screwed gold chatons, blued screws, an elaborate whiplash precision index adjuster and the hand-engraved balance cock are visible through the sapphire-crystal caseback.
“With three classic complications, the manufacture calibre L101.1 is one of our most complex movements. Each one in itself already constitutes a technical feat; when combined, they represent a far greater challenge. For our designers and our watchmakers in equal measure, since the tweaking and tuning process of all mechanisms requires an exceptionally high degree of dexterity and technical expertise.”
Anthony de Haas, Director of Product Development, A. Lange & Söhne
Technical Specifications:
1815 RATTRAPANTE PERPETUAL CALENDAR
Ref. 421.056FE
| Movement | Lange manufacture calibre L101.1, manually wound, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; plates and bridges made of untreated German silver; balance cock engraved by hand |
| No. of movement parts | 631 |
| No. of jewels | 43 |
| No. of screwed gold chatons | 4 |
| Escapement | Lever escapement |
| Oscillator | Shock-resistant screw balance, superior-quality balance spring manufactured in-house, frequency of 21,600 semi-oscillations per hour, precision beat adjustment mechanism with lateral setscrew and whiplash spring |
| Power reserve | 42 hours when fully wound |
| Functions | Time indicated in hours, minutes and subsidiary seconds dial with stop seconds; rattrapante chronograph with minute counter; perpetual calendar with date, day of week, month, moon phase and leap year; power-reserve indicator |
| Operating elements | Crown for winding the watch and setting the time; two chronograph buttons, one button to operate the rattrapante mechanism; separate recessed correctors for advancing the date, day of week, month and moon phase |
| Case dimensions | Diameter: 41.9 millimetres; height: 14.7 millimetres |
| Movement dimensions | Diameter: 32.6 millimetres; height: 9.1 millimetres |
| Crystal and transparent caseback | Sapphire crystal (Mohs hardness 9) |
| Case | 18-carat white gold |
| Dial | Solid pink gold |
| Hands and appliques | Rhodiumed gold; blued steel hour, minute, minute counter and rattrapante hand, rhodiumed steel chronograph hand |
| Strap | Hand-stitched alligator leather, dark brown |
| Buckle | Deployant buckle in 18-carat white gold |
| Limited edition | 100 watches, edition number engraving, boutique-exclusive |
For more information please visit A. Lange & Söhne