Tomorrow's new Moon cannot be seen, yet stargazers know well that the planetoid is still there floating in space.
Terraluna's movement and patent-pending orbital Moon-phase display.
This occurs when the Moon is positioned in approximate alignment between Earth and Sun — its unlit hemisphere facing the Earth resulting in the seeming disappearance upon the night sky.
The shy new Moon marks the beginning of the lunar cycle, with the orbit around Earth challenging watchmakers to display the Moon phase on fine timepieces.
Among A Lange & Sohne 2014 editions, Richard Lange Perpetual Calendar Terraluna comes with an innovative lunar display on the back of the model, while a simpler format appears on the front of Langematik Perpetual, Grand Lange 1 Moon Phase and the pink-gold Lange 1 Tourbillon Perpetual Calendar.
Terraluna's sapphire crystal caseback reveals the movement and patent-pending orbital Moon-phase display depicting the constellation of the Earth, Moon and Sun.
Pink-gold Lange 1 Tourbillon Perpetual Calendar.
Claimed to be a first for a wristwatch, the display follows the location of the Moon relative to the Earth, with the progression of the Moon phase observed through an aperture in the star-studded celestial disc covering an underlying lunar disc.
In addition, an Earth disc is located in the centre, rotating about its own axis once a day whereas the Moon takes around 29 days to circle the Earth.
The timepiece's planetary gear system is engineered to present a correctly-displayed Moon phase. The mechanism is even claimed to reproduce the synodic month of 29 days, 12 hours, 44 minutes and three seconds so precisely that it takes 1058 years before a correction by one day is required.
Besides the technical appeal, the German maison enhanced the movement's aesthetics with a special coating process on the solid white-gold discs. The celestial disc, for example, boasts a deep-blue surface adorned with high-contrast twinkling stars.
The back looks beautiful but Terraluna's front appears rather busy, with four jumping displays for date, day, month and leap year; while a large minute circle overlapping smaller hour and second sundials indicate the time.
The dial is inspired by a historic 1807 regulator from the Mathematics and Physics Salon's timepiece collection.
The regulator format was created for precise timekeeping while providing an accurate display of the minutes and seconds. It was one of the ingenious designs by Johann Heinrich Seyffert, who transformed Dresden into Germany's hub of precision horology in the early 19th century.
Based in Glashutte, about 30km from Dresden, the Lange family further laid the cornerstone of Saxony's precision watchmaking, with second-generation Richard Lange probably the most inventive family member.
His numerous discoveries include the 1930 patent application of a small admixture of beryllium to improve the rate characteristics of balance springs.
Designed for utmost accuracy, Richard Lange models feature in-house manufactured balance springs of which not many maisons have such production.
Available in pink and white gold versions, the 45.5mm Richard Lange Perpetual Calendar Terraluna also has a constant-force escapement with in-house made remontoir spring that further promotes its precision.
While Terraluna was launched at SIHH 2014, a new version of the Langematik Perpetual debuted in September at the opening of A Lange & Sohne's boutique in Moscow.
The stylish redesign combines a white-gold case with a black solid-silver dial, whose Moon-phase display is a paragon of precision as well. Assuming the watch runs without interruption, it deviates from the true position of the Moon by just one day every 122.6 years.
The timepiece runs with a self-winding SAX-0-MAT calibre, the name coming from "Saxonia", "zero" and "automatic". When the crown is pulled, the patented Zero-Set mechanism makes the seconds hand jump to the zero position, thus simplifying the watch's synchronisation.
Langematik Perpetual is a member of the Saxonia watch family, which pays tribute to the region's heritage in artisanal skills. The craftsmanship can be seen on the back of the watch, with the hand-decorated movement showcasing exquisite engraving, finishing and polishing techniques by A Lange & Sohne's artisans.
Grand Lange 1 Moon Phase with the lunar display positioned within the hour and minute circle.
A white-gold version of Langematik Perpetual.
Pink-gold Lange 1 Tourbillon Perpetual Calendar.
