IWC Portugieser Perpetual Calendar with the double moon

IWC Portugieser Perpetual Calendar with a double moon IW503401In the Portugieser Perpetual Calendar with the double moon, the moon phase and its mirror image show the state of the moon in both the northern and southernhemispheres.

For the first time, the model no longer features the countdown display that shows the number of days remaining until the next full moon. Instead, the watch designers have transformed the subdial with the double moon display into a star-studded night sky the same colour as the large dial, so that the moon and stars appear to hover in infinite space.

A further new feature of the design is the introduction of the railway-track-style chapter ring typical of the Portugieser, which puts the model closer in appearance to the classic original. The dial appears more balanced and elegant because the subdials for the date and week are also the same colour.

The perpetual calendar shows not only the lunar cycles but also the seconds, minutes, hours, date, day, month and year in four digits. Mechanically programmed, the calendar takes into account the different lengths of the months and even the leap years.

Nevertheless, every 100 years (2100, 2200 etc.) a leap day that would normally be due is omitted,which means that a watchmaker will have to advance the calendar on 1 March. Another intervention will be necessary in 2300 in order to replace the current century slide, which bears the numbers 20, 21 and 22, with a new one for the years 2200 to 2499.

Having to visit the watchmaker’s once every 100 years is probably a tolerable inconvenience for present and future owners of the Portugieser Perpetual Calendar with the double moon.