SIHH 2014: A. Lange & Söhne presents the Richard Lange Perpetual Calendar Terraluna

After the presentation in 2013 of the Grand Complication and more recently of the Grand Lange 1 Moon-Phase, the 2014 edition of the SIHH is the time for A. Lange & Söhne to reveal another masterpiece, showing once again the expertise of the manufacture in complicated movements and innovation. The Richard Lange Perpetual Calendar “Terraluna” combines a perpetual calendar, a regulator display, a 14 days power reserve and a constant force escapement. Already impressive in itself, the front dial is not the only that attracts us; the “Terraluna” features on its movement side a brand new orbital moon-phase display.

The Richard Lange Perpetual Calendar “Terraluna” is a 45.5mm watch available in both a pink or white gold case. The front face may look quite busy, but regarding at the level of information it brings, the dial is well design. The regulator-layout is build around three circles – the minutes on the top – the hours on the right side – the seconds on the left side. The perpetual calendar is presented in an unusual way for A. Lange & Söhne. Except the outsize date at 12, the days, months and leap-year are exposed in small apertures (at 2 for the leap-year, at 4 for the months and a 7 for the days). At 6, you’ll also find the 14 days power reserve indicator. A lot of information on that dial but the legibility remains very good.

The big novelty is definitely the back of the “Terraluna” that features a very complicated and unseen orbital moon-phase. The display consists of three discs and gives the moon-phase but also the position of the sun and the position of the moon relatively to the earth.

How does it work…

On the celestial disc, the moon is visible through a round aperture and orbits around the earth, anti-clockwise, once in a month. It brings both the moon-phase indication as well as the position of the moon relatively to the earth.

The progression of the moon phases can be observed through the aperture and the position of the sun is occupied by the balance. On new-moon days, the dark moon stands between the earth and the sun. It appears as a bright sphere on the opposite side of the earth on full-moon days. Thus, the position and phase of the moon are indicated simultaneously.

At the same time, the earth on the centre disc rotates on its axis once a day. It is daytime on the half that faces the sun, or the balance, and night-time on the other. Round that orbital disc, a 24h scale provides a time-of-day reference for the northern hemisphere.

These three discs are made of solid white gold with a special coating process that absorb all the non-blue colour spectra for a deep blue result and high contrast stars. The mechanism reproduces the synodic month of 29 days, 12 hours, 44 minutes, and 3 seconds, meaning that it takes 1058 years before the display needs to be corrected by one day.

The movement of the “Teraluna” features the outstanding level of finish that we are used to with A. Lange & Söhne, meaning a three-quarter plate in untreated German silver and hand finishing of all the parts. The new L096.1 movement features a twin barrel for a power reserve of 14 days. To compensate the high energy of these spring barrels, the watch features a constant-force mechanism (remontoir spring). In ten-second intervals, it releases an identical portion of the available energy to the balance, thus assuring that the torque remains constant. The result is a stable amplitude and high rate accuracy from the first day to the last.

Some specifications:

• Case: pink or white gold 45.5mm, 16.5mm height, sapphire crystal on front and back
• Functions: Regulator-layout with hours, minutes and seconds; perpetual calendar with outsize date, day of the week, month and leap year; power reserve indicator; orbital moon-phase display with day/night indicator on the movement side
• Movement L096.1: 37.3mm diameter and 11.1mm height, 787 parts, 80 jewels, 14 days power reserve. Frequency 21,600vph, constant force escapement. Adjusted in 5 positions. Three-quarter plate made of untreated German silver, finished by hand, balance cock engraved by hand.
• Operating: Crown for winding the watch and setting the time; push piece for advancing all calendar displays; recessed push pieces for separate correction of month, day of week, and moon phase

The official retail price including tax/VAT is € 185.000 Euro for the pink gold version and € 186.000 in white gold.

More info: www.alange-soehne.com