First seen in 2016, the A. Lange & Söhne Datograph Perpetual Tourbillon Honeygold ‘Lumen’ now exhibits its technical finesse and design assets in the dark.
The latest version of this stunning timepiece includes three classic complications with supplementary functions. DATOGRAPH designates a flyback chronograph with the typical Lange outsize date. The flyback mechanism allows quick consecutive time measurements because the three switching steps stop, reset to zero and start, are executed with one single push of a button. The minute counter assures unambiguous readings of stopped times: it jumps to the next increment at the precise moment when the chrono seconds hand completes the 60th second.
PERPETUAL refers to the perpetual calendar with its instantaneously switching displays. Due to its stunning mechanical precision, the forward-looking moon-phase display will only deviate from the true lunation by a single day after 122.6 years. The rapid-correction button at 10 o’clock can be used to simultaneously advance all displays by one day. Three correctors on the flank of the case make it possible to separately adjust the moon-phase display, the day of the week, the month and the leap year.
The attribute TOURBILLON refers to the one-minute tourbillon with a stop-seconds mechanism; it offsets the influence of gravity on the going train. Once a minute, it rotates the rate-governing components ‒ balance, lever and escape wheel ‒ inside a filigreed cage about its own axis around the stationary fourth wheel. The highly aesthetic and horologically intricate device substantially improves rate accuracy of mechanical timepieces.
The evolved manufacture calibre L952.4 (above) beats at the heart of the DATOGRAPH PERPETUAL TOURBILLON HONEYGOLD ‘Lumen’ and consists of 684 parts being assembled twice. The classic column-wheel chronograph is equipped with a freely oscillating Lange balance spring as well as a Lange balance wheel with eccentric poising weights, assuring excellent rate stability across the entire power reserve of 50 hours. It is calibrated to a frequency of 18,000 semi-oscillations per hour (2.5 hertz), allowing measurements with an accuracy of one fifth of a second ‒ in the light of the minute scale featuring an impressive total of 300 markers. Typical Lange quality hallmarks such as bridges made of untreated German silver, polished gold chatons and blued screws can be admired through the sapphire-crystal caseback.
“In 2016, the A. Lange & Söhne engineers created one of our technically and aesthetically most sophisticated timepieces with the DATOGRAPH PERPETUAL TOURBILLON. It unites three classic complications – a column-wheel chronograph with a precisely jumping minute counter, perpetual calendar with instantaneously switching displays and a tourbillon with a stop-seconds mechanism, – and useful supplementary functions. The challenge presented also consisted in complementing the precisely harmonised interaction between the highly complex mechanisms with an optimally balanced dial design. The DATOGRAPH PERPETUAL TOURBILLON HONEYGOLD ‘Lumen’ spotlights the distinctive technical and aesthetic features of the watch to an even greater degree, allowing these to be experienced in the dark for the very first time. Once more, we live up to our ambition to test the limits of mechanical horology and cast new light on sophisticated complications.”
Anthony de Haas, Director of Product Development, A. Lange & Söhne
Technical Specifications:
| DATOGRAPH PERPETUAL TOURBILLON HONEYGOLD “Lumen” Ref. 740.055FE | |
| Movement | Lange manufacture calibre L952.4, 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 |
| No. of movement parts | 684 |
| No. of jewels | 56, one of which a diamond endstone |
| No. of screwed gold chatons | 5 |
| Escapement | Lever escapement |
| Oscillation system | Shock-resistant balance with eccentric poising weights; superior-quality balance spring manufactured in-house, frequency of 18,000 semi-oscillations per hour |
| Power reserve | 50 hours when fully wound |
| Functions | Time indicated in hours, minutes, and subsidiary seconds; tourbillon with stop seconds; flyback chronograph with precisely jumping minute counter; tachymeter scale; perpetual calendar with outsize date, day of week, month, leap year; day/night indicator; moon-phase display |
| Operating elements | Crown for winding the watch and setting the time; two chronograph buttons, rapid-correction button for all calendar indications, one corrector each for the moon phase, the day of week and one for month and leap year |
| Case dimensions | Diameter: 41.5 millimetres; height: 14.6 millimetres |
| Movement dimensions | Diameter: 32.6 millimetres; height: 9.0 millimetres |
| Crystal and transparent caseback | Sapphire crystal (Mohs hardness 9) |
| Case | 18-carat HONEYGOLD® |
| Dial | Sapphire crystal, coated |
| Hands | Hour and minute hands: 18-carat HONEYGOLD®, luminous; day-of-the-week and month hands: 18-carat HONEYGOLD®; minute counter and subsidiary seconds hands: 18-carat gold, black-rhodiumed; chrono seconds hand: steel, luminous |
| Strap | Hand-stitched alligator leather, dark-brown |
| Buckle | Deployant buckle in 18-carat HONEYGOLD® and 18-carat white gold |
| Limited edition | 50 watches, edition number engraving |
For more information please visit A. Lange & Söhne