At Watches and Wonders 2024, the sophisticated timepiece combining a flyback chronograph with a precise jumping minute counter, perpetual calendar and tourbillon with a stop-seconds mechanism will be presented ‒ for the first time in Lange-exclusive honey gold (Honeygold^®) and as a “Lumen” version, limited to 50 watches.

Introduced in 2016, the Datograph Perpetual Tourbillon featuring three eponymous complications occupies an imposing position in precision watchmaking. While each complication alone already represents a technical feat, the most formidable challenge is not only to achieve the perfect interaction between the different highly complex mechanisms, but to devise a well-organised and easy-to-read face. The Datograph Perpetual Tourbillon Honeygold “Lumen” now also exhibits its technical finesse and design assets in the dark.

The complications described below make the timepiece into a comprehensive work of art: 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 60^th second. The functionality of the chronograph is complemented with a tachymeter scale for determining average speeds; it is located on the outer circumference of the dial made of coated sapphire crystal.

PERPETUAL refers to the perpetual calendar with its instantaneously switching displays. With a view to long-term time measurement, it is based on the Gregorian calendar and takes into account the different durations of the months, including leap-year deviations. 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.

200 years after the tourbillon was invented, A. Lange & Söhne presented its stop-seconds mechanism in 2008, taking a huge step towards optimising this device. It made it possible to stop the tourbillon at will and set the watch to one-second accuracy for the very first time, regardless of the angular position of the balance or the orientation of the tourbillon cage.

When the crown is pulled, a lever mechanism releases the stop lever, which guides the arresting spring in the direction of the balance. The contact pressure of the spring instantly stops both the balance and the tourbillon cage. When the crown is pushed home, the balance and tourbillon are released, and the watch instantly starts running again. The filigreed, precise mechanics and the fascinating choreography orchestrated around the fourth wheel can be observed through the sapphire-crystal caseback of the watch.

Not only does the Datograph Perpetual Tourbillon Honeygold “Lumen” distinguish itself thanks to its ingenuous mechanisms but also because of the lucid arrangement of the displays, translating technical finesse into an exceptional design language. Comprising an equilateral triangle formed by the Lange outsize date in a framed twin aperture beneath 12 o’clock and the two subsidiary dials, the dial architecture is a well-organised model of clarity, despite the abundance of displays. The subsidiary seconds dial, the day of the week and the day/night indicator are located on the left-hand side, while the precise jumping minute counter, the month and the leap year can be found on the right. The moon-phase display at 6 o’clock is harmoniously embedded in the ensemble.

The Datograph Perpetual Tourbillon Honeygold “Lumen” also reveals its radiant personality in the dark ‒ thanks to the semi-transparent dial and the luminous coating that make the displays and functions glow. The darker the surroundings, the more prominent the luminous elements appear. The hour and minute hands are inlaid with a luminous compound, while the chrono seconds hand is completely coated. The hands of the subsidiary seconds, month, day of the week and minute counter move above luminous subsidiary dials. The subjacent luminous compound causes the inscription on the circumferential dial ring with the minute scale and tachymeter scale to glow.

The luminous outsize date, a distinctive highlight, first featured in the Grand Lange 1 “Lumen” in 2013, rendering the ingenious disc mechanism visible. Guaranteeing that the outsize date display also glows just after the daily switching sequence, presented a considerable challenge. In typical Lange fashion, the solution was found: the tens cross and units disc are coated with a luminous compound and printed with black numerals, making it possible to closely observe the illustrious date switching performance at midnight.

The evolved manufacture calibre L952.4 beats at the heart of the Datograph Perpetual Tourbillon Honeygold “Lumen”: it consists of 684 parts and is 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.

The dimensions of the Datograph Perpetual Tourbillon Honeygold “Lumen” remain unmodified. With a diameter of 41.5 millimetres, the honey-gold case boasts a height of 14.6 millimetres. The Datograph Perpetual Tourbillon Honeygold “Lumen” is the sixth model of the limited “Lumen” edition, and subsequent to the Zeitwerk Honeygold “Lumen” launched in 2021, only the second model that combines the particular hardness and incomparable resplendence of honey gold with the luminous “Lumen” coating.

“In 2016, the A. Lange & Söhne engineers created one of our technically and aesthetically most sophisticated timepieces with the Datograph Perpetual Tourbillon,” explains Anthony de Haas, Director of Product Development. “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.”

Dresden watchmaker Ferdinand Adolph Lange laid the cornerstone of Saxony’s precision watchmaking industry when he established his manufactory in 1845. His precious pocket watches remain highly coveted among collectors all over the world. The company was expropriated after World War II, and the name A. Lange & Söhne nearly vanished. In 1990, Ferdinand Adolph Lange’s great-grandson Walter Lange had the courage to relaunch the brand.

Today, Lange crafts only a few thousand wristwatches per year, predominantly in gold or platinum. They are endowed exclusively with proprietary movements that are lavishly decorated by hand and assembled twice. With 66 manufacture calibres developed since 1990, A. Lange & Söhne has secured a top-tier position in the world of watchmaking. Brand icons such as the Lange 1 with the first outsize date in a regularly produced wristwatch, and the Zeitwerk with its precisely jumping numerals display, rank among the company’s greatest successes.

Exceptional complications such as the Zeitwerk Minute Repeater, the Triple Split, and the so far most complicated model, the Grand Complication presented in 2013 in a six-watch limited edition, reflect the manufactory’s determination to achieve ever new pinnacles in its tradition-steeped horological artistry. Launched in 2019, the sporty-elegant Odysseus marks the beginning of a new chapter for A. Lange & Söhne.

Reference	:	740.055FE
Limited edition	:	50 watches Edition number engraving
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
Diameter	:	32.6 millimetres
Thickness	:	9.0 millimetres
Components	:	684
Jewels	:	57, one of which a diamond endstone
Screwed gold chatons	:	5
Escapement	:	Lever escapement
Oscillation system	:	Shock-resistant balance with eccentric poising weights Superior-quality balance spring manufactured in-house
Frequency	:	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	:	18-carat Honeygold®
Diameter	:	41.5 millimetres
Thickness	:	14.6 millimetres
Glass & caseback	:	Sapphire crystal (Mohs hardness 9)
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
Bracelet	:	Hand-stitched alligator leather, dark-brown
Clasp	:	Deployant buckle in 18-carat Honeygold® and 18-carat white gold