The Rolex Oyster Perpetual Sky-Dweller features a dual time zone that is intuitive to read and simple to use. The Sky-Dweller allows travellers to adjust the watch to different time zones during a journey, while maintaining a constant, clear display of reference time – the time at home or at their usual place of work.
Local time is indicated by the conventional centre hour, minute and seconds hands. It can be set quickly and easily by means of a mechanism that allows the hour hand to be adjusted independently in one-hour increments both
forwards and backwards, so that changing the local hour affects neither the minute and seconds hands nor the reference time in the second time zone. Since the watch is not stopped, accuracy is preserved.
Travellers can read the reference time via a rotating off-centre disc visible on the dial. A fixed inverted red triangle points to the wearer’s chosen reference time. The disc’s 24-hour display allows travellers to clearly distinguish daytime hours from night-time hours in the distant time zone (for example, 10 p.m. versus 10 a.m.). At any moment and in any location, they know if it is an appropriate time to contact someone on the other side of the world.
The date change is linked to local time and occurs within a few milliseconds at midnight. Thus, the date displayed in the aperture is always the current date in the wearer’s local time zone.
The Oyster Perpetual Sky-Dweller is equipped with a revolutionary annual calendar that offers unparalleled robustness and reliability for such a complex watchmaking function. The secret lies in its ingeniously simple design.
This annual calendar’s qualities are attributable to a patented mechanism named Saros, after the astronomical phenomenon of the same name, and which functions using only four additional gear wheels.
This annual calendar automatically differentiates between 30-day and 31-day months. It therefore displays the correct date through a year and requires only one adjustment on 1 March – February having only 28 or 29 days. This kind
of calendar simplifies life for the wearer, who no longer needs to remember to change the date several times during the year.