Introduced into the market in 2000, this complicated wristwatch incorporates a perpetual calendar with leap year indicator, mechanically tracks the time of sunrise and sunset for the designated city indicated on the recessed inner ring following its owner's request, in this case Moscow, and accurately shows the difference between mean solar time and sidereal time. The Equation of Time and its 423 components is another example for Audemars Piguet's dedication to the art of fine watchmaking.

The equation of time is the difference between true solar time and mean time. True solar time, given by sundials, varies from day to day because of the Earth's elliptical orbit, and according to the longitude of the point of observation. Meantime, given by watches, ignores these variations and for every day of the year mathematically divides time into equal hours.