Limited to 50 pieces, the Datograph Perpetual Tourbillon Honeygold 'Lumen' 740.055FE was presented by A. Lange & Söhne at Watches and Wonders 2024 as one of the watches celebrating twenty-five years of the Datograph. It brings together three major complications, a flyback chronograph with a jumping minute counter, a perpetual calendar with Lange's outsize date and a one-minute tourbillon with stop-seconds, in a case of Honeygold, the manufacture's proprietary hardened gold alloy reserved for limited editions. It is also the sixth member of Lange's Lumen series, which began in 2010 and is defined by a semi-transparent dial and displays that glow in the dark. That combination makes it one of the most complex and distinctive watches in the current collection: a grand complication that can be read at night, with the mechanism of its calendar partly visible through the dial by day. It was the first time the Datograph Perpetual Tourbillon had been made in Honeygold, and the first time it joined the Lumen series, so the edition marks a double first for one of the manufacture's most complicated models.
The Honeygold case measures 41.5 mm in diameter and 14.6 mm in height, with polished and brushed surfaces and the Datograph's rectangular chronograph pushers. The dial is made of sapphire crystal with a smoky tint that remains permeable to ultraviolet light, so the luminescent elements beneath it can be charged evenly while the mechanism of the perpetual calendar stays partly visible. Lange's outsize date at 12 o'clock is the most striking example: its discs are coated with luminescent material and glow brightly in the dark, and the workings behind them can be seen through the tinted sapphire. On the left, one subdial shares its space between small seconds, weekday and a day/night display, and the right subdial combines the 30-minute chronograph counter with the month and leap year, both treated to glow as well. At 6 o'clock, a moon phase whose disc is made of tinted sapphire and treated with the same luminescent material sits between them. A chapter ring carrying the tachymeter scale also glows. Honeygold hands and applied Honeygold indices complete the dial. The watch is worn on a brown alligator strap with a deployant buckle in Honeygold and White Gold.
Inside is a hand-wound movement of 684 parts that runs for 50 hours when fully wound. Its flyback chronograph is controlled by a column wheel and features the jumping minute counter that has characterised the Datograph since 1999. The perpetual calendar switches instantly at midnight: the outsize date, formed by an octagonal tens disc and a circular units disc, and the day and month hands all jump to their next positions at once, rather than changing gradually. The calendar tracks months of every length and the leap-year cycle, and Lange states that the moon phase deviates from the true lunar position by only one day in 122.6 years, provided the watch runs without interruption. The one-minute tourbillon, positioned on the movement side and visible through the sapphire caseback, is equipped with Lange's patented stop-seconds, which freezes the cage as soon as the crown is drawn out, allowing a to-the-second start. Unlike earlier versions of the model, this edition omits the arc-shaped indicator of remaining running time, a change that made room for the glowing tachymeter ring. The movement is finished with German silver, Glashütte ribbing and hand engraving, and it is assembled twice.
The Datograph Perpetual Tourbillon was launched in 2016 in Platinum as the most complicated member of the Datograph family, combining the chronograph and perpetual calendar of the Datograph Perpetual with a tourbillon. A White Gold edition with a solid Rose Gold dial followed in 2019. The Lumen series, meanwhile, began in 2010 and has since included models such as a Datograph Up/Down and a Zeitwerk, each exploring how Lange's complications can be made legible in darkness without sacrificing their elegance. For the Datograph's twenty-fifth anniversary in 2024, Lange combined both lines for the first time in this Honeygold edition, presented alongside a Datograph Up/Down in White Gold with a blue dial. The choice of Honeygold, used by Lange only for special and limited pieces since 2010, underlined the significance of the anniversary. Within the manufacture's catalogue, the 740.055FE stands as one of its most elaborate limited editions, bringing together the manufacture's chronograph expertise, its calendar mechanics, its tourbillon technology and its most unusual dial treatment.
The 740.055FE appeals to collectors who seek the most ambitious expressions of A. Lange & Söhne's watchmaking. With only 50 pieces, three major complications and a Honeygold case, it is among the rarest and most sophisticated watches the manufacture has produced in recent years. Its Lumen dial gives it a character entirely its own, transforming a traditional grand complication into a watch that reveals a second personality in the dark, while its semi-transparent sapphire offers a view into the calendar mechanism during the day. It will interest collectors of the Lumen series, admirers of the Datograph family and those who value Honeygold editions. On the wrist, the warm gold, smoky dial and brown strap create a rich and unmistakable presence. For a collection built around Lange's grand complications, it is a centrepiece; for enthusiasts of mechanical innovation, it represents a rare meeting of tradition, technical mastery and imaginative design.
