Moon-phase display

Moon-phase display

Moon-phase display
calibre A. Lange und Söhne L922.1

A disc that rotates under the dial and is visible through an aperture. It shows the moon phases from full to new, generally as seen from the Northern Hemisphere.

Such mechanisms basically are known, particularly so in complex watches, and are used for instance as a secondary display in wristwatches. However, the lunar phases seen by an observer have an appearance that differs depending on his position onthe globe, in particular on the latitude, in a way already explained in the European patent application EP 1 445 672 originating from the International Watch Corporation (IWC).