Commit TV Yagi Column ~《Series of Questions You're Too Afraid to Ask Now Vol.21》【Introduction to Luxury Watches】What is the "Moon Phase"? Explaining the Functions and How to Use Them That You Surprisingly Don't Know~

Good evening everyone!

This week, we have a new series, In this new project, we will explain the basics of luxury watches in an easy-to-understand way, for those who are not very familiar with luxury watches and those who want to learn more about them.

This is the 21st time

[ Introduction to Luxury Watches ]: " Moon Phase "

If you are a watch lover, you have probably seen the "moon phase" at least once. Its biggest feature is its appearance, which accentuates the design of the watch and adds a touch of glamour. However, not many people can explain what role it plays apart from its appearance, or how it works. In this article, we will explain the functions, mechanisms and usage of the "moon phase". Please enjoy until the end.

What is Moon Phase?

" Moon Phase " = " A mechanism that expresses the phases of the moon on the dial "

The "Moon Phase" watch, which allows you to see the night sky with the moon and stars in a small window, represents the shape of the moon as seen from the earth. It is often recognized as the "lunar age" which indicates the period from one new moon to the next, but the lunar age is called the "moon age". The cycle of one cycle of the "moon phase" is basically 29.5 days, although it varies depending on the brand.

The History of the Moon Phase

There are many theories about when the moon phase first came into being, but it is said that the basic mechanism was completed around the 16th century. In the 18th century, it was first installed in a pocket watch by the genius watchmaker Abraham-Louis Breguet, and at the time, the waxing and waning of the moon was deeply connected to navigation and natural phenomena, making it an indispensable part of people's lives.

It began to be used in wristwatches in the 1940s . Only a few luxury watch brands carried it, but now, with technological advances, many brands have adopted it. However, it is still a complicated mechanism, and even brands that use the moon phase are limited to a few models. As mentioned above, whereas it was previously a practical mechanism, it is now mostly used for its aesthetic beauty and uniqueness.

How the Moon Phase works

The moon phase is displayed using a rotating disc.

The window that displays the rotating disk has two semicircles at the opening, which cover the lower part. When the moon is in a horizontal position, it is hidden by the semicircular part of the window, which indicates a new moon. Then, as the rotating disk rotates clockwise, the moon gradually becomes more visible. When it rotates 90 degrees, it reaches a full moon, and then it gradually disappears again, returning to a new moon.

As mentioned at the beginning, many brands set the "moon phase" as a cycle of 29.5 days. To set this with gears, it is necessary to set a gear that rotates once every 59 days, which is a multiple of 29.5 , and this gear advances one tooth each day. The reason for using multiples of 29.5 days is because an odd tooth such as 0.5 cannot be used.

How to set the Moon Phase

Most moon phases go around once every 29.5 days, but the actual lunar cycle is a little off, so there is an error of about one day every three years.

If it stops or the deviation becomes too large, you will need to adjust it manually. Here we will show you how to adjust the moon phase.

Setting with the crown

If your watch has a crown that adjusts the moon phase, you can set it by turning the crown. When adjusting the moon phase, it is best to refer to a lunar calendar. You can easily find a lunar calendar online, so find the date of the most recent full moon and set the moon phase on your watch to the full moon. Then, advance the crown by the number of days that have passed since the full moon and the setting is complete. You can also set it with a new moon, but it is easier to tell when it is completely hidden, so it is easier to tell with a full moon.

When setting with push button

There are also watches that use a push button to adjust the "moon phase." This push button is not a chronograph push button, but a small button on the side of the case that is operated by pressing it with a pin. The basic setting method is the same as when setting with the crown: when the moon is full, press the push button the number of days that have passed and the setting is complete.

summary

I have explained about the Moon Phase, but what do you think?

Not only can you enjoy the complex mechanism, but the beautiful appearance that changes every day is also a big attraction of the "Moon Phase." Try to find one that has the individuality of each brand.

I hope that after reading this article, you will become interested in luxury watches!

see you!