How does the perpetual calendar work?
Time is fleeting, even that of every watch lover. Or should I say, especially that of every watch lover. Because with every glance at the precise automatic watch, the second hand always reminds us that time is unstoppable and therefore fleeting.
Nevertheless, there is a way to wear a piece of infinity on his wrist: The perpetual calendar..
Perpetual calendar is a function that allows mechanical watches to display the date automatically including leap years. Unlike traditional calendars that need to be adjusted manually, perpetual calendars can automatically calculate the number of days in the month and February in leap years.
The perpetual calendar - a flagship of the watchmaker's art
What is the perpetual calendar?
The perpetual calendar is one of the great complications in the world of watches. It makes it possible to correctly read the date in any year.
The complication automatically recognizes how many days each month has, which day of the week it is and whether it is a leap year or not, so that the wearer always gets the correct date displayed without having to readjust anything himself.
Well-known perpetual calendars include, for example, the Da Vinci Perpetual Calendar from IWC and the Royal Oak Perpetual Calendar from Audemars Piguet, but above all the Grand Complications from Patek Philippe, the father of the perpetual calendar. But many other well-known names, such as Vacheron Constantin or A. Lange und Söhne, also venture into the complex calendar.
However, the luxury watch manufacturer Rolex does not incorporate perpetual calendars. The Rolex Sky-Dweller, which was introduced in 2012, features an annual calendar that resembles the perpetual calendar but falls short of its capabilities.
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The features of the complication
You can recognize the perpetual calendar by the fact that the current date, day of the week, month, and year are displayed on the dial.
Most often, this data is displayed with the help of smaller subdials. However, the presentation of the information varies among different models. It is not uncommon for perpetual calendars to be combined with other complications. This particular composition solves each manufacturer individually.
The limits of complication - 100 years of infinity
It is important to note, however, that a perpetual calendar cannot guarantee 100% accuracy. Most watches with this feature can work correctly until the year 2100. After that, there may be deviations.
Within four hundred years, exactly three leap days are omitted. This means that in 2100, 2200, and 2300, a day is skipped even though logically there should be a leap day in these years. These are called secular years.
However, there are some Movements that can take even this into account.
How does the perpetual calendar work
Most perpetual calendars use a complex mechanism consisting of a variety of gears, levers and springs.
At the same time, the various manufacturers, which are able to master the extremely demanding complication, have also developed different mechanisms.
Essentially, the technology behind it can be explained as follows.
The most important component is the program wheel. This rotates exactly once around its own axis within 4 years. The 48 notches that the gear has are equivalent to the 48 months in a four-year cycle. The depth of the recesses is decisive. This is because the deeper a notch is, the earlier the gear shifts to the following month. Logically, the four February months must have the deepest recesses because they are the shortest months. One recess must be minimally higher because it belongs to February in the leap year with 29 days.
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The history of the perpetual calendar
The first time this function was made was in 1764 by watchmaker Thomas Mudge in a pocket watch.
More than one hundred and sixty years later, Patek Philippe took up this idea again and introduced the first wristwatch with a perpetual calendar in 1925.
The luxury watch manufacturer from Geneva played a pioneering role in the development of the perpetual calendar. In 1941, the company introduced the first wristwatch with a chronograph and perpetual calendar to the market. Nowadays, Patek's Grand Complications, which combine several major complications, are famous in the world of watches.
Indeed, it was once again Patek Philippe that, twenty years later, introduced the first perpetual calendar in an automatic watch. Nowadays, the perpetual calendar in automatic watches, especially when combined with other complications, is considered the pinnacle of watchmaking.
What to consider with the perpetual calendar
Is it worth buying a perpetual calendar?
If you're now wondering whether it's worth buying a perpetual calendar watch, the answer depends on you. It's certainly convenient to have a timepiece that always displays the correct date. However, solely for this functionality, it's not worth spending huge amounts of money on such a watch. Especially considering that this information is readily available on every smartphone anyway.
The fascinating thing about complications is the outstanding craftsmanship behind them. If you are captivated by this and the idea of wearing a timeless masterpiece of watchmaking appeals to you, then you should definitely consider making a purchase.
Of course, prices vary depending on the manufacturer and model. The least expensive models start in the upper four-figure range on the second-hand market. The upper limit is open-ended.
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How do you set a perpetual calendar?
The most recommended approach is actually not to set your perpetual calendar at all, by either wearing the watch daily or storing it in a watch winder.
If the movement does come to a stop, there are a few important points to keep in mind in order to avoid damaging the delicate watch mechanism.
Simply adjusting the watch to the correct date will not suffice, as in this case the day of the week and the month will not match. With a perpetual calendar, each date has its own position in the movement. This means that the time the watch has not been running must be accounted for month by month, day by day, in a fast forward manner.
As with other mechanical watches, it is important to avoid touching the crown between 11:00 PM and 1:00 AM, as various mechanisms are engaged at this time. Those who cannot resist the temptation risk causing serious damage to their wristwatch.
If, however, the date has been advanced too far ahead, do not under any circumstances attempt to turn it back. Doing so can cause devastating damage to the delicate mechanism. Instead, it is recommended to let the power reserve run out and wait until the time is back in sync with the date on the watch.
Conclusion
Ultimately, the perpetual calendar is one of the most complex and fascinating complications in the world of watches. The luxury watchmaker Patek Philippe based in Geneva played a significant role in the development of the perpetual calendar, and is considered its grandfather, so to speak.
Even though the exact eternity often only lasts for 100 years, the refined craftsmanship behind it is extraordinarily remarkable. The perpetual calendar makes it possible for numerous generations to read the date from the same watch.
One thing is for sure, if you decide to buy and wear a perpetual calendar, you will never forget the date for the rest of your life.
Source cover image: IWC
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Q&A
What is a perpetual calendar?
The perpetual calendar is a complication that allows for the display of the current date, day of the week, month, and year.
How does the perpetual calendar work?
A specially developed program wheel makes it possible to distinguish between longer and shorter months, as well as leap years.
Does the perpetual calendar really run forever?
Yes and no. Most models, with a few exceptions, need to be readjusted every hundred years.
What should I keep in mind when setting the perpetual calendar?
Never set the watch backwards and definitely not between 11:00 PM and 1:00 AM.
About the author
Alexander Weinberger
For me, the most fascinating thing about watches is the interplay between precise craftsmanship and artistic development. In a watch movement, hundreds of small parts have to be put together precisely so that they form a large whole.
