IWC Schaffhausen Portugieser Sidérale Scafusia 46 mm Black Dial Platinum Black Leather Strap IW504101

The dial, in the style of a classic Portugieser, features a constant-force tourbillon together with displays for the 96-hour power reserve and sidereal time, which, among other things, is needed to find the same star each night in the same position. The reverse side is a fabulous astronomical module calculated precisely to reflect the owner’s wishes. From a previously defined location, the rotating night-sky disc shows more than 500 stars and constellations with such detail and precision that it would quicken the pulse of any astronomer. Making the necessary allowances for summer time and winter time, the watch also displays the times of sunrise and sunset, sidereal time and a perpetual calendar with the leap years. In view of the enormous amount of work involved and the more than 200 individual configurations possible, only a few watches are produced each year.