With this self-winding luxury chronograph A. Lange & Söhne combines for the first time a wristwatch chronograph and perpetual calendar, which are exactly the two “opposite” extremes of timekeeping short-term and permanent.
With its flyback function the chronograph can instantly be set to zero with a single keystroke during the time of measurement, whereafter the new measurement starts immediately. The perpetual calendar shows day of week, month, leap year, day/night indication, moon phase and big date. The latter must be switched forward by a day only in 2100, making it become the “Eternal big date”. The moon phase indication is so precise that it must be corrected for one day only after 122 years.