Watches - Feature Article

The Moonphase: The Most Romantic Of All Complications

The longest day of the year is fast approaching, marking a return to longer, brighter evenings (as I write this, it is pouring down - typical). In the northern hemisphere, the summer solstice, or longest day of the year, takes place between June 20 and 22 each year. This year it falls on Saturday, June 20. Because we are here to talk watches, it would be wrong not to be specific. And here in the UK we will get 16 hours and 38 minutes of daylight. The sun will rise at 4.43am and set at 9.21pm. The solstice officially marks the beginning of astronomical summer, day and night will be at almost equal length on this day.

Sunset Image

Ancient cultures knew that the sun’s path across the sky, the length of daylight, and the location of the sunrise and sunset all shifted in a regular way throughout the year. They built monuments, such as Stonehenge, to follow the sun’s yearly progress.


From the chronograph to the jump hour, the horological world boasts a number of mechanical complications that boggle the mind and excite the heart. None more so than the Moonphase complication. It is without a shadow of a doubt, the most romantic complication, and as you can imagine, combines artistic crafts with functionality.  From a functionality standpoint, it displays the phase of the moon as it changes from full to new and back again over the course of a month. Behind the dial of a typical moonphase watch is a disc with two identical moons on it. This disc rotates one complete cycle every twenty-nine and a half days.  Frustratingly to watchmakers around the world, the true lunar cycle lasts 29 days, 12 hours and 44 minutes, or 29.53 days. Being off by .03 days per month means that the entire moonphase cycle will be off by one full day every two years, seven and a half months. To overcome this, a 135-tooth gear was developed to drive modern moonphase disks, ensuring accuracy to just one day off every 122 years.

Its origins go back thousands of years, to the second century BC, predating the birth of the modern clock by more than 1700 years. The earliest found example of the mechanical moonphase is in the Antikythera, an Ancient Greek mechanism. Then came astronomical clocks built into churches and cathedrals during the Renaissance and persisted through the 1500’s like this one here from Prague. The sixteenth century brought about the use of the moonphase complication in standalone clocks. The complex grandfather clocks built in Germany and England often featured a moonphase complication, then incorporated into pocket watches and by the twentieth century into wristwatches.

Ochs und Junior
Ochs und Junior

The moonphase is still to this day one of the most produced complications in all of watchmaking. With Patek and Lange boasting watches with moonphase complications with over 1000 years of accuracy, while micro brand Ochs und Junior nearly 3500 years and Andreas Strehler over two million years!  While the technical is side is fascinating, and mind blowing in equal measure, I happen to find the various smiles and glares of the design of the moons fascinating. Discussions rage online in forums and on social media as to what type of look or frown a moon is pulling at any given time. Generally speaking, there is some real artistry that goes into enamelling and other finishing.  A couple I love from the current stock online are the curious face of the Blacpain Villeret in Platinum, the square Vacheron Toledo, the decidedly modern Heritage Chonométrie from Montblanc and the super complex Patek 5270G perpetual calendar. Whichever gets your seal of approval, the joy that comes from starring up into the nights sky and then back down to your watch to check the comparison will never fail to amaze.

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