so here it is Loungers the final hint until the unveiling :-)
A Most Precice Moonphase
The Vacheron Constantin moon phase system is so precisely calculated that it requires correction only once every 1027 years and 108 days. The four indications shown here display the new moon and full moon, the first quarter and third quarter of the moon cycle. The moon goes through a complete moon phases cycle in about one month. More accurately, the synodic period or lunation and is exactly 29.5305882 days. The outer ring on this dial registers the number of each elapsed day of the 29.5305882 day cycle. In a period of 1027 years and 108 days the Vacheron Constantin moon phase will deviate by just one day.