The latest ticking chef d’oeuvre from Saxon watchmaker A. Lange & Söhne is a horological triple threat and then some. Unveiled this week at SIHH 2016 in Geneva, the A. Lange & Söhne Datograph Perpetual Tourbillon incorporates three major complications with five supplementary functions.
The three complications are a flyback chronograph, a perpetual calendar, and a tourbillon (not a complication in the classical sense but widely regarded as one by many, and certainly a mark of high watchmaking expertise). As is typical with Lange, however, there is more to each of these mechanisms, as we discover by examining each word in this new model’s moniker.
“Datograph” is A. Lange & Söhne’s designation for the combined mechanism of a column-wheel chronograph, with a precisely jumping minute counter and a flyback function, and the typical Lange “outsize” date indication. For this watch, Lange incorporated the system that it unveiled to great acclaim in its Datograph Up/Down model, with its three major technical advances in chronograph design: a column-wheel mechanism to reliably control the stopwatch function, a jumping minute counter to crisply display elapsed times, and a flyback function enabling the timing of consecutive events with short reaction times.
“Perpetual” refers, of course, to the watch’s perpetual calendar, one of the most prized of horological complications, and here again, Lange goes the extra mile. All the calendar indications — including the aforementioned outsize date, the day-of the week, the month, and the leap-year displays in subsidiary dials – switch instantaneously, providing unambiguous readings at all times. Lange says that the watch’s owner — or more likely, his descendant — would not need to correct the mechanism, by one day, until March 1 of the year 2100. Furthermore, the ultra-precise moon-phase display is set to deviate from the true lunation by a single day after 122.6 years. The watch includes three correctors for the separate adjustments of the moon-phase display, the day, and the combined month/leap-year indications. There’s also an additional rapid-correction pusher at 10 o’clock that can be used to conveniently update all displays simultaneously.
Finally, the “tourbillon” — visible through the sapphire crystal caseback and the open tourbillon bridge — houses the rotating escapement inside a filigreed cage. Working in concert with the free-sprung balance spring made in-house at Lange’s manufacture in Glashütte, Germany, it ensures solid rate accuracy throughout the watch’s 50-hour power reserve, which is indicated at the end of the tachymeter scale (AUF for up, or fully wound, AB for down, or stopped). For the first time in a Lange watch with both a tourbillon and a chronograph, the balance beats at a rate of 18,000 (2.5 Hz) instead of the conventional 21,600 vph. The practical result of this decision is that elapsed chronograph times can be displayed with an accuracy of 1/5 second. Furthermore, with the patented stop-seconds mechanism, the owner can instantly stop the balance wheel inside the tourbillon cage with a simple pull of the crown, meaning the watch can be set with one-second accuracy.
The A. Lange & Söhne Datograph Perpetual Tourbillon has a 41-mm platinum case (14.6 mm thick) and a black dial made of solid silver. Limited to just 100 pieces worldwide, it comes on a hand-stitched alligator leather strap with a platinum deployant buckle. The retail price is 295,000 euros. Below are a few live shots taken of the watch during Lange’s SIHH presentation.