This year at SIHH, A. Lange & Söhne presented one of its most complex and visually breathtaking masterpieces — the Richard Lange Perpetual Calendar Terraluna. Beyond the familiar regulator-style dial layout (inspired by the 1807 Regulator watch), what truly amazes is found on the reverse side: an orbital moon-phase display that precisely depicts the relative positions of the Earth, Moon, and Sun — allowing the wearer to sense cosmic time without looking at the sky.
The dial design takes inspiration from Johann Heinrich Seyffert’s 1807 regulator pocket watch, with minutes at 12 o’clock, hours at 5 o’clock, and seconds at 7 o’clock. Interestingly, the hour and seconds subdials are reversed compared to the original, as a wristwatch prioritizes hours and minutes over seconds — unlike the regulator, which emphasizes precision in minutes and seconds.
Flipping the watch reveals the orbital moon-phase system, one of Lange’s most poetic innovations. Despite its name, it displays not only the moon’s phase but also the orbital movements of the Earth, Moon, and Sun.
To read it: the gold balance wheel represents the Sun, the central blue disc shows the Earth, and the outer blue ring displays the Moon and stars. As the balance wheel (Sun) oscillates, the Earth disc rotates — the side facing the balance wheel represents daytime. The Moon circle revolves around the Earth, showing its current orbital position and visible phase.
The mechanism precisely tracks the synodic lunar cycle of 29 days, 12 hours, 44 minutes, and 3 seconds, requiring correction only once every 1,058 years.
A. Lange & Söhne Richard Lange Perpetual Calendar Terraluna
18K rose gold / 18K white gold case, 45.5mm diameter, 16.5mm thickness, sapphire crystal front and back, L096.1 movement, 80 jewels, 21,600 vph, 14-day power reserve, alligator leather strap, 18K rose/white gold buckle.
Complications: Perpetual calendar, orbital moon-phase.
