IWC: The Most Complicated Watch

The exterior offers customisation; apart from the anti-reflective sapphire crystal, customers can personally selectIWC watcha series of 46 mm case materials and dial designs, as well as the colour and material of the strap.

The new watch can display both solar time and sidereal time. The 24-hour sub-dial at the 12 o'clock position on the dial is for sidereal display, equipped with hour and minute hands; the hour and minute hands in the centre of the dial are for solar time display; the spherical tourbillon small seconds dial at the 9 o'clock position is for the solar time seconds display, and the 4 o'clock and 5 o'clock positions show the 96-hour power reserve.

The newWatchNot only does it have an eye-catching dial, but its case back, engraved with the night sky and a perpetual calendar, is equally unique. The perpetual calendar is displayed in a circular pattern, counting continuously from day 1 (1 1) to day 365 (12 31); in a leap year, the letter "LY" is displayed. The perpetual calendar also connects to the edge of the case back, including displays for the current time of day, sidereal time, and sunrise/sunset times, accompanied by an arrow indicator running on a 24-hour cycle. The night sky design in the centre features a yellow engraved horizon, showing the night sky position chosen by the wearer. At the same time, the wearer can also choose the constellations to display the night sky of a specific geographical location. The background of the night sky is equipped with a polarising filter, with day and night times displayed in grey and blue respectively.

This watch is equipped with a 94900 calibre manual movement, featuring a constant-force mechanism that offsets the power consumption of the mainspring barrel and stably transmits power to the balance wheel. Meanwhile, two mainspring barrels are placed in parallel to ensure that the constant force is maintained for at least two days, while the seconds hand set on the titanium tourbillon cage advances every second. The tourbillon continues to operate evenly with the rhythm of the balance wheel, with a vibration frequency of 2.5 Hz, which is 18,000 vibrations per hour.

Earth's time is based on the length of the mean solar day, known as solar time. The benchmark for sidereal time is an infinitely distant star, which is perpendicular to the observation point at the beginning and end of the observation period, measuring the time it takes for the Earth to rotate on its axis. The two types of days have different lengths; the mean solar day is 24 hours, and sidereal time is approximately 4 minutes shorter than mean solar time.