The first wall clocks indicated the moon's position in the early 16th century. With the quartz crisis in the 1970s, the mechanical clock lost its importance and this astronomical complication. It was not until 1983 that Blanc pain brought the moon phase display back to the world of mechanical watches with the caliber 6395. The watch like Rolex cellini moonphase was such a success that many other manufacturers added the moon phase display to their ranges. Today there are moon phase displays in eyes in almost every price category, but with different levels of precision. A comparatively simple mechanism enables...