The lunar phase or phase of the Moon is the shape of the directly sunlit portion of the Moon as viewed from Earth. The lunar phases gradually and cyclically change over the period of a synodic month (about 29.53 days), as the orbital positions of the Moon around Earth and of Earth around the Sun shift.
The Moon's rotation is tidally locked by Earth's gravity; therefore, most of the same lunar side always faces Earth. This near side is variously sunlit, depending on the position of the Moon in its orbit. Thus, the sunlit portion of this face can vary from 0% (at new moon) to 100% (at full moon). The lunar terminator is the boundary between the illuminated and darkened hemispheres.
Each of the four "intermediate" lunar phases is around 7.4 days, but this varies slightly due to the elliptical shape of the Moon's orbit. Aside from some craters near the lunar poles, such as Shoemaker, all parts of the Moon see around 14.77 days of daylight, followed by 14.77 days of "night". (The side of the Moon facing away from Earth is sometimes called the "dark side of the Moon", although that is a misnomer.)
Content taken from the page "Lunar phase". In: Wikipedia, The Free Encyclopedia.. Date of last revision: 28 August 2019 20:28 UTC. URL: https://en.wikipedia.org/w/index.php?title=Lunar_phase&oldid=912933366
DAVOSA presents with the current limited edition of the Newton Pilot Moonphase Chronograph a high-quality chronograph based on the ETA / Valjoux 7751. In addition to numerous other setting options, the mechanical watch has a moon phase display.
Displaying the current phase of the moon on the dial of a mechanical watch may not sound like a big challenge. But in practice, it is complicated. The main difficulty lies in the fact that the moon does not follow an exact 24-hour rhythm. Generations of watchmakers have tried to display the moon’s orbit of 29 days, 12 hours, 44 minutes and 2.9 seconds as realistically as possible on the dial of a watch.
To adjust the moonphase function pull out the crown to position 2 as explained in the instructions provided. You can then move the moon around in a clockwise direction. The simplest way to set the moonphase dial is to wait until a full moon and then set the full moon icon at the top of the dial. However if you would like to set the moon in its exact phase immediately it is necessary to research the current phase of the moon either online or by an almanac. Remember it will take almost a month for the Moonphase dial to turn so it will be hardly noticeable on a daily basis.
A moon phase calendar until 2025 is included in the delivery of the Newton Pilot Moonphase Chronograph. You can also see it directly here.