Does Your Watch Have A Moon Phase?

The lunar cycle has long been associated with potent forces. Here, SARAH ROYCE-GREENSILL decodes the magic and mysticism of horology’s most enchanting complication

Watchmakers have long been inspired by celestial cycles, and the modern moon-phase functions championed by Vacheron Constantin, Jaeger-LeCoultre and IWC Schaffhausen serve to showcase each house’s elite level of craftsmanship

From mental health to menstruation, the belief that the moon influences health and behavior dates back thousands of years. An old wives’ tale posits that more babies are born around a full moon, while the word ‘lunacy’ originally referred to insanity brought on at different phases in the lunar cycle, and the position of the moon played a fundamental role in medicine during the 16th century. It’s no wonder that the moon became a cornerstone of the earliest forms of timekeeping.

The first example of a ‘moon-phase’ display – the Antikythera mechanism – was used to predict astronomical events in Ancient Greece. Later, the moon-phase function appeared in clocks and pocket watches; by the early 20th century, leading watchmakers displayed a waxing and waning moon in mechanical wristwatches. Today, the moon phase remains one of the most aesthetically pleasing and sought-after complications of the horological world.

In a standard moon-phase complication, a 59-tooth gear powers a disc depicting two full moons, half of which is visible on the dial. Every 24 hours, the wheel moves forward one notch, so the visible moon waxes and wanes over the course of time. When the first moon has waned, the second moon comes into view, and the cycle begins again. The mechanism needs adjusting only every two-and-a-half years, and more complex versions contain a 135-tooth gear, providing accurate indications of the moon’s position for 122 years.

Alongside technical proficiency, the moon-phase function allows watchmakers to showcase their creativity. Pros portray the moon using a raft of complex and specialized artistic skills, from intricate enameling and gem-setting to miniature painting and engraving.

“An accurate moon-phase function is wonderfully complex to execute and a visual reminder of a watchmaker’s skill, as well as adding animation and interest to a dial,” says Tracey Llewellyn, editor of Telegraph Time. “They may rarely have any practical use today, but they are a link to the past, when the sun, moon and stars indicated the passing of day and night.”

The moon phase is a complication that allows us to escape our daily life, to dream and to project ourselves in the stars. In French, there is an expression that states a dreamy person is one that has their head in the moon
Lionel Favre, Jaeger-LeCoultre’s product design director

Recently, celestial motifs have peppered our wardrobes and jewelry boxes. The popularity of zodiac signs, talismanic symbols and healing crystals attests to our desire to seek solace in a higher power. Our fascination with the otherworldly influence of the cosmos parlays into a renewed interest in moon-phase watches; that little lunar symbol being a reminder of the mystical power of the moon.

When considering which complications to incorporate into Vacheron Constantin’s elegant Egérie line, a moon-phase model was an obvious choice. “The moon phase has a poetic personality and is aesthetically interesting to work with,” says style and heritage director Christian Selmoni. “It was clear that the moon phase would perfectly fit the design of the Egérie and match the feminine character of the collection.”

Jaeger-LeCoultre first created moon-phase calibers for pocket watches in the late 1800s, and the complication continues to appear on the house’s most celebrated models. The midnight-blue moon of the ‘Rendezvous Automatic Day & Night Moon-Phase’ matches the hands and alligator strap, while a mother-of-pearl moon glimmers on the starry sky-inspired reverse face of the ‘Reverso One Duetto’ Moon. A classic moon-phase indicator adds to the timeless appeal of the ‘Master Ultra-Thin Automatic Moon-Phase’, but the star of the show is the new ‘Rendez-Vous Dazzling Moon Lazura’, where the moon appears amid diamond constellations on an electric-blue lapis lazuli dial.

“Jaeger-LeCoultre watchmakers have always been inspired by celestial cycles,” says Lionel Favre, the maison’s product design director. “The moon phase is a complication that allows us to escape our daily life, to dream and to project ourselves in the stars. In French, there is an expression that states a dreamy person is one that has their head in the moon; there is a poetic connection between the moon and dreams.”