Portuguese Perpetual Calendar

The moon phase display in the perpetual calendar is extremely accurate, requiring only one day of adjustment after 577.5 years. Even on days when the sky is covered with clouds, the phases of the moon can still be accurately tracked.
The moon phase display on the Portuguese Perpetual Calendar is accurate to just one day in 577.5 years. With its perpetual calendar, four-digit year display, and seven-day self-winding movement with Pellaton winding system, this elegant timepiece has almost everything one could wish for. Four subdials on the silver-plated dial display the moon phase, date, power reserve, month, and day of the week, as well as integrated small seconds. Powering the watch is an IWC-manufactured 52000 series caliber movement featuring a solid red gold rotor and blued steel screws. It is equipped with a dark brown alligator leather strap.