A. Lange & Söhne has announced the ninth of 10 limited-edition timepieces commemorating the 25th anniversary of the iconic, original Lange 1, and the third one equipped with the Saxon manufacture’s ultra-precise lunar complication. Here is what you need to know about the Little Lange 1 Moon Phase “25th Anniversary” edition.

The Little Lange 1 Moon Phase debuted in 2017

The Little Lange 1 Moon Phase made its debut in 2017. At 36.8 mm in case diameter, it is as a more modestly sized cousin to the original Lange 1 Moon Phase, at 38.5 mm, and its successor, the Grand Lange 1 Moon Phase, at 41 mm. (All of these, of course, emerged from the horological wellspring that is the original Lange 1 from 1994, which essentially put the revived, post-Cold War A. Lange & Söhne brand on the map.)

The moonphase is accurate for 122.6 years

Like its predecessors in this special Anniversary series, the watch features a solid silver argenté-colored dial with deep blue printed hour markers and date numerals, blued steel hands, and a blue-filled, relief-engraved numeral “25” on the movement’s balance cock denoting this watch as one of an extremely limited series of just 25 pieces. The features the off-center hours-and-minutes subdial, outsize date, and AUB/AUF (up/down) power reserve indicator made famous by the first Lange 1 model, along with its signature complication, a moon-phase indicator with a hand-engraved lunar disk depicting the moon on a star-filled sky.

The disk makes one full revolution around its own axis every 24 hours, in synch with the rhythm of day and night. The white-gold moon makes its orbit precisely every 29 days, 12 hours, 44 minutes, and 3 seconds, meaning the indicator doubles as a day-night indicator and that it would be 122.6 years before it requires a one-day correction.

A special engraving on Caliber L121.2

The watch is equipped with the manual-winding Caliber L121.2, with plates and bridges made of untreated German silver, an in-house-manufactured, freely oscillating balance spring, a 21,600-vph frequency; and a fully wound power reserve of 72 hours. The case, as are all its brethren in the 25th Anniversary collection, is made of 18k white gold and mounted on a blue alligator leather strap, with hand-stitched gray contrast stitching and a white-gold pronged buckle. Limited to just 25 pieces, the Little Lange “25th Anniversary” edition is priced at $43,500).