Moonphase Watches and the Art of Celestial Timekeeping

Widely regarded as the most evocative complication in watchmaking, the moonphase possesses a mysterious power to captivate those who have laid eyes upon. It is simply a work of art and a culmination of watchmaking excellence.

The moon has given inspirations to calendars and folklores, and whose gravitational forces preside over tides. A horological tribute, the moonphase recreates its stunning beauty on a watch.

As much a hymn of the moon as it is a distinctive function within the myriad of watchmaking complications, the moonphase brimming with heritage and significance. It has been reinterpreted over and over with watchmakers eager to put their own signatures on this beloved feature.

Where did Moonphase Watches Originate?

Mankind has been fascinated with the moon since ancient times. Created in the second century BC and only discovered in 1901, the Antikythera mechanism was built by the Greeks to predict, among others, lunar eclipses and moonphases. It is the oldest known example of analogue computers.

As the moon influences the Earth’s tidal range, knowing the phases of the moon is crucial to marine navigation in the absence of modern technological aid. For example, spring tides occur during new and full moons, resulting in a large tidal range. This leads to stronger currents and extreme tidal levels at both ends, making navigation around a shallow or narrow channel a formidable challenge to mariners.

While the Antikythera mechanism is a museum piece, other historical clockworks bearing the moonphase are still in perfect working order today. A great example is the Prague Astronomical Clock located in the city’s old town square.

Installed in 1410, this mediaeval structure features an astronomical dial, three hands, a solar plate, a rotating zodiacal ring, an outer rotating ring, and several figures. It tracks phases of the moon and the moon’s position in the sky. The clocktower’s magnificence has inspired generations of watchmakers, seeking to recreate its complexity and style on a finer scale.

The moonphase complication first appeared on grandfather clocks in the 17th century, followed by pocket watches a century later. In 1762, Thomas Mudge created the first-ever perpetual calendar pocket watch with a moonphase. Miniaturisation progressed steadily. In 1925, Patek Philippe unveiled the first moonphase-equipped wristwatch, setting a trajectory for moonphase watches that remains unbroken till today.

The moonphase is designed to mirror the current lunar phase, and visualise how the moon appears in the sky, commonly in the Northern Hemisphere.

Streamlined to help with understanding, there are eight distinct phases of the moon: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter and waning crescent.

A moonphase disc features two opposing moons, with one appearing on the aperture at any given time. Traditionally a lunar cycle is understood as 29.5 days.

The combination of two moons in the same moonphase indicator enables a watchmaker to use a driving wheel with 59 teeth to complete a full rotation every 59 days. A complete rotation thus correctly shows each lunar phase from new moon to waning crescent twice. This overcomes the technical limitation of making a wheel with 29.5 teeth.

Nevertheless, to be absolutely precise, this 29.5-day lunar cycle is an approximation. The synodic lunar cycle lasts 29.5305881 days, or specifically 29 days, 12 hours, 44 minutes and 2.8 seconds. If the moonphase disc uses a 59-tooth driving wheel, it will deviate from the true lunar cycle after a while. A whole day is lost every two years and seven-and-a-half months.

The pursuit of precision has motivated watchmakers to refine their moonphase mechanisms to be even more accurate, including wheels with additional teeth or a whole-new discrete mechanism. Featuring complex or patented mechanisms, modern high-precision moonphase complications require no adjustment for at least 122 years.

While accounting for the synodic lunar cycle seems an impossible task on a mechanical moonphase watch, it has not deterred watchmakers from continuously innovating and finding new solutions.

The moonphase, in general, is grouped into bosom and radial. In luxury watchmaking, watchmakers overwhelmingly prefer the bosom moonphase as this classic execution affords superior precision, finer nuances and artistic freedom.

A bosom moonphase features a dedicated moonphase aperture underpinned by a rotating moon disc, with the moon travelling across the opening to reveal different phases of the moon. On the other hand, a radial moonphase features a scale comprising an extra hand pointing to the phases of the moon.

To put it simply, a bosom moonphase relies on a rotating disc, while a radial moonphase relies on a hand. Thanks to technical leeway the bosom moonphase can accomodate, watchmakers can design and implement their desired interpretations.

The bosom moonphase features a fully rotating disc inscribed with two moons, with one appearing on the aperture, while the opposite advances silently underneath before coming to the fore in the next cycle.

With an artistic free rein, watchmakers express their visions using exotic and precious materials, such as crafting the moon from mother-of-pearl or the star-studded night sky from aventurine, and hand-engraving or mirror-polishing the moonphase to unearth great finesse.

Cortina Watch is an authorised dealer for the most exclusive names in watchmaking. Tastefully appointed, Cortina Watch galleries showcase a wide range of selections from heritage to contemporary luxury watches, including moonphase watches, thoughtfully curated to appeal to both discerning collectors and the curious looking to acquire their first luxury watches.

The boutiques offer unparalleled access to expert guidance and accredited after-sales service, with watch collectors’ satisfaction our priority. Exclusive editions from Franck Muller, Parmigiani Fleurier BOVET, and H. Moser & Cie. are available at select Cortina Watch boutiques. Cortina Watch is the destination for authentic moonphase watches in Malaysia.

The allure of moonphase watches is as timeless and perpetual as the moon hovering over the night sky. On the lunar-adorned dial where art and watchmaking intersect, function and poetry collide to produce a paean celebrating its brilliance. This enduring popularity has helped moonphase watches retain their values over time, making them a wise investment.

At Cortina Watch, expert advisers are on hand to guide collectors in a personalised experience, from exploring new moonphase watches to securing the perfect watch. Book an appointment with us today and experience the magic of moonphase watches.

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