The Richard Lange Perpetual Calendar “Terraluna” was launched at the SIHH 2014, featuring a constant force escapement, a perpetual calendar with Lange’s oversized double date window, a power reserve of 14 days and an oversized moon phase display on a rotating orbit to the back.

Waxing and waning of the moon has always fascinated mankind, even though it is well known now that its shape and size only appear to be changing during its journey around our planet. The changes are in its appearance due to its constellation relative to the earth and the sun. This phenomenon is perfectly reproduced in the “Terraluna”. Its patented orbital moon phase display can be admired through the sapphire crystal back of the watch, showing the current moon phase as well as the positions of the moon and sun as an observer in the northern hemisphere would see them. Once correctly set, the moon phase display is so precise that if the watch runs without interruption, it will take 1058 years before a correction by one day is required.

The regulator dial, a feature historically used in observatories and for navigation because of the accurate display of minutes and seconds, was inspired by the 1807 regulator made by Johann Heinrich Seyffert from the renowned timepiece collection of the Mathematics and Physics Salon in Dresden, Germany. The timekeeping functions are indicated in three individual displays: the minutes at the top, hours to the lower right, seconds to the lower left. The calendar display consists of the oversized double date and three smaller apertures for the leap year, day and month. The power reserve is visible through an aperture below 6 o’clock, indicating days instead of the hours.

The three-quarter plate cal. L096.1 movement is manufactured to A. Lange & Söhne’s rigorous standards, featuring twin barrels and a constant force escapement with remontoir spring. It consists of 787 components, including 80 jewels and one screwed gold chaton. Every part is hand decorated and assembled, the balance cock is hand engraved.

This technically impressive and very elegant timepiece is doubtlessly one of the most collectible perpetual calendar watches of recent production. Sold to Benefit the ETH Zürich Foundation: The ETH Zurich Foundation builds bridges between ETH Zurich and companies, foundations, organisations and private individuals to ensure that ETH Zurich can drive forward in its strategic endeavours and maintain its leading global position.

As Switzerland’s foremost technology foundation, it specifically supports ETH Zurich in achieving its objectives in education and research. Partners gain access to wonderful partnerships and visionary programmes shared with Europe’s best university.

With these activities, the ETH Zurich Foundation aims to encourage progress and enable donors to experience the real benefits of their commitment. It brings together society, industry and sci-ence. Exploring the limits of knowledge together and creating added value is what makes this partnership so fascinating and important.