Lot 59

A. Lange & Söhne

TERRALUNA

A Glashuette wristwatch in mint condition, with perpetual calendar, power reserve indicator and orbital moon phase - with original box, Lange-booklet, Lange-guarantee seal dated September 23, 2016, operating instructions, setting pin, loupe and cleaning cloth

The three-part regulator dial of the RICHARD LANGE PERPETUAL CALENDAR "Terraluna" was inspired by a precision chronometer crafted by master watchmaker Johann Heinrich Seyffert of Dresden (1751-1817). As not to interfere with the readability of the dial, the moon phase is visible on the back through the sapphire caseback and shows the positions of the moon, Earth and the sun as seen from the Northern hemisphere. In the centre, Earth revolves around its own axis in 24 hours; the position of the sun is represented by the balance, with a revolving 24 hour scale for reference. On the outer celestial disc, the cut-out for the moon revolves around Earth in slightly more than 29.5 days. Once correctly set, the so-called orbital moon phase display is so accurate that if the watch runs without interruption, it will take 1058 years before it needs a correction by one day. Another technical highlight is the 14-day power reserve with constant-force mechanism, which releases a fixed amount of torque to the balance every ten seconds and ensures the constant amplitude. The energy to drive the calendar mechanism continuously builds up via a cam disk and releases at midnight, so that all calendar indications jump simultaneously thanks to spring-loaded levers and always remain unambiguously visible.