From the A. Lange & Sohne website:
1815 MOON PHASE
On the occasion of Emil Lange’s 150th birthday in 1999 and to pay tribute to his horological accomplishments, his watchmaking descendants crafted this masterpiece as a symbolic monument in his honour. The moon-phase display is so precise that it only needs to be corrected by one day every 1058 years. The 1815 MOON PHASE was built in 1999 and 2000. The edition was limited to 250 pink-gold and 150 platinum models.
1815 Moon Phase Hommage to Emil Lange