Last week I had the opportunity to join a exclusive viewing of the Portuguese Siderale Scafusia. Benoit de Clerck, Managing Director of IWC North East Asia introduced the watch followed by a short video presentation.

The event was held in a private room at Cafe Grey in Hong Kong. It was a beautiful night and the perfect setting to learn more about this incredible watch that took ten years of research and development to produce and has over 500 individual parts.

The watch is by far one of IWC’s most complicated watches and combines a constant force tourbillion and small seconds at 9 o’clock, solar and sidereal time, and a 96 hour power reserve.

This completely new constant force tourbillion is beautifully designed and guarantees an even rate for 48 hours while the second hand jumps once a second. After two days the mechanism switches from constant force mode to normal mode as indicated by the one fifth of a second movements in the second hand.

If you look closely at the dial you will notice the watch features a globe of the world engraved with lines of latitudes and longitudes offering a hint that this watch is more complex then it seems. Sidereal time is displayed on a small subdial located at 12 o’clock while the center hands of the watch show solar time. Now I must admit it had been awhile since I took a science course and wasn’t exactly sure what the difference was between solar time and sidereal time.

At the risk of oversimplification – solar time is what we normally think of as a day in everyday life – exactly 24 hours – or the time it takes the earth to orbit around the Sun.

Sideral time is the time kept with respect to the distant stars – is actually 4 minutes shorter per day – or the time it takes the earth to make one complete rotation. In other words because stars are so far away from us – the sidereal day represents the time it takes the view an exact point in the sky from the same location on earth – or 23 hours, 56 minutes and 4.1 seconds later.

Now things get really interesting as soon as you flip the watch over. The Sidereal features a number of complex astronomical functions including a celestial chart that shows the stars in the night sky from a specific point on earth chosen by the owner.

There is a perpetual calendar that shows the number of the day of the year together with a leap year display. And there is a celestial chart that shows the horizon, ecliptic and celestial equator, indication for the day, night and twilight, and a display for sunrise and sunset.

The Sidereal is impressive on the wrist and can be personalized to the owners specifications. I can only imagine how beautiful the watch would have been in platinum with a black dial (as shown in the catalogue). But with all these highly complex complications the watch is not small (nor is the price tag). The case height is 17.5mm with a diameter of 46mm.

I want to give my special thanks to Gaelle Devins, Winnie Ho and Eric Au Yeung for hosting such a great evening. Usually I would have included a few pictures of the lovely meal but not surprisingly the Siderale commanded all of our attention for the entire evening.

Timezone Feature