The moon phase, which allows you to see the phases of the moon on the dial, is a fascinating mechanism. By gaining a deeper understanding of its mechanism and history, it will be easier to choose an IWC moon phase watch. We will introduce the appeal of IWC moon phase watches and current models equipped with this mechanism.
The Moon Phase mechanism evokes a sense of the microcosm
The moon phase is a romantic mechanism that evokes the feeling of a microcosm on the dial. We will explain its mechanism and history, and explore the appeal of the perpetual moon phase developed by IWC.
How the moon phase works
The moon phase is a feature that displays the phase of the moon (the waxing and waning of the moon) on the dial of a watch. Many brands incorporate various designs of moon phase displays into their models.
The average cycle of the moon is approximately 29.5 days. The moon phase display incorporates a rotating disc with 59 teeth, twice the length of this cycle, allowing the disc to display all phases of the moon in half a revolution.
Most moon phase watches have a design in common: a disc depicting the moon or the night sky is visible through a small window. The disc depicts two moons, as the moon cycle is shown twice in one revolution.
The History and Usefulness of the Moon Phase
The basic mechanism of the moon phase is said to have been created as early as the 16th century, but it wasn't until the 1940s that it began to be incorporated into wristwatches.
Although it is now a unique visual feature, the moon phase was originally created for practical purposes: people used their eyes to look at the night sky and predict the various effects of the moon on Earth.
Unlike today, when information about the moon is easily available on the web, in the past, if it was cloudy for several days in a row, it would be impossible to tell the phase of the moon. Moon phase devices, which allow you to know the phases of the moon even on days when the moon is hidden, were very useful for people who needed to know the phase of the moon.
IWC creates a perpetual moon phase
A typical moon phase watch will have an error of about one day every three years because, when using a rotating disc with 59 teeth, it is slightly out of sync with the cycle of the moon's phases.
To reduce this error, IWC incorporated a rotating disc with 135 teeth into the moon phase to allow for more precise movement, and in 1985 they released the "perpetual moon phase," which reduced the error to just one day every 122 years.
Models equipped with a perpetual moon phase will likely not require adjustment after the initial setting, but the perpetual moon phase model released in 2017 has since improved its accuracy to approximately one day every 577.5 years.
How to set the moon phase
If the lunar cycle changes or your watch stops, you'll need to manually adjust the moon phase. Learn how to do this using both the crown and the pushers.
Turn the crown while referring to the moon phase calendar
If your watch uses a crown to adjust the moon phase, you can adjust the moon phase by turning the crown. The crown is also used to adjust the time and date, so be sure to check your watch's instruction manual for instructions on how to set them.
When setting the moon phase, it is common to refer to a lunar calendar and adjust it accordingly. First, set the moon phase to the "moon phase 0" position, which corresponds to a new moon, and then advance the crown by the number of days that have passed since the most recent new moon.
You can also adjust it based on the full moon at "lunar age 15." You can easily find a lunar calendar by searching online.
Press the push button to adjust
Some watches have moon phases adjusted with a push button rather than a crown.
The push button in this case refers to a small button that is operated by pressing a pin, and is typically located on the side of the case near the top of the crown.
The method for adjusting the moon phase is the same as when using the crown, referring to the moon phase calendar. When the moon is new or full, press the push button to advance to the current moon phase. Each press advances one day.
