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IWC Portuguese Sidérale Scafusia – Hands-On Review

Posted by Tom Mulraney on

“Non est ad astra mollis e terris via” – “There is no easy way from the earth to the stars”

― Seneca

Man has always been fascinated by space. Ever since our earliest memories we have gazed upwards, seeking to comprehend the vastness around us and our place within it. It is not surprising then that we have become enamoured with the beauty of the stars defiantly shining in our night sky, even in spite of our best efforts to dim their light with our over-illuminated cities. The only problem though is that the stars are so far away and reaching them, as our friend Seneca aptly points out above, is not easy (in fact it’s pretty much impossible.) So, why not do the next best thing and bring the stars to you?


Ok, so maybe Swiss watchmaker IWC cannot actually bring the stars to you but they can certainly create a gorgeous representation of the night sky that you can carry on your wrist with you everywhere you go. It’s called a Celestial Chart, which is a depiction of the stars in the night sky as seen from a specific point on the Earth’s surface, and you will find one on the caseback of each custom made IWC Portuguese Sidérale Scafusia. The chart also displays the apparent orbit of the Sun in the course of the year as well as the celestial equator. Best of all because each watch is made to order the chart is always calculated based on the customer’s instructions, meaning that no matter where you travel in the world you will always have your night sky with you.

Look a little closer though and you will notice that this is more than just a pretty picture. The caseback also places host to complications such as a perpetual calendar displaying the absolute day of the year, together with indicators for sunrise and sunset as well as solar and sidereal time. It can be a little confusing at first but everything has its place, you just need to understand how to read each of the indicators.



For a start the Perpetual Calendar shows the number of the day of the year on two separate day counter discs (ordinal date), together with a leap year display. So in the photo here, it is the 27th (25 + 2) day of Year 1. Next is the solar time (i.e. the normal time) which is shown on the outer 24-hour ring and indicated by the red triangle with the dot below it. Note that when daylight savings time is in effect you need to add one hour to this time.


The inner 24-hour ring meanwhile displays Sidereal or ‘Sidérale’ Time (or star time) as indicated by the yellow triangle with the star below it. Sideral Time by the way is a time-keeping system used by astronomers, on a 24-hour display. A sidereal day is the time taken by a star to cross the same meridian twice, and there is a more precise indicator of this on the dial side as well (but more on that in a second.) Sunrise and sunset also are indicated on the outer 24-hour ring by the two red triangle hands. Finally, the daytime, night-time and twilight are indicated by the darkening or lightening of the planisphere (very cool).


Of course as beautiful (and as useful) as the Celestial Chart is, you may find it pretty difficult to tear your eyes away from the front of the watch to look at the back. You see, never before in IWC’s 140+ year history has the brand ever created a watch that features such an array of astronomical displays combined with numerous complications. Add to that the fact that IWC says there are over 200 ways to customize this timepiece to suit your personal tastes and you quickly realise there is a lot to take in here.


The first thing you will probably notice is the large tourbillon at 9 o’clock, which all but dominates the dial with its impressive presence. Although a watch equipped with a tourbillon is nothing new here on WatchAnish, this one is particularly notable because it has been combined with a constant-force mechanism. This combination guarantees a precise and even rate for a period of at least 48 hours or roughly half of the watch’s total 96-hour power reserve. In constant-force mode, the seconds hand jumps once a second. After this, the drive switches to normal mode, meaning that it advances at the rate of one-fifth of a second. The tourbillon’s cage and upper section is crafted from titanium whilst the rhodium-plated escape-wheel and nickel-silver stop-wheel bridge have been painstakingly hand-chamfered, and I have to say is really quite spectacular to look at.




In addition to the tourbillon, the dial also offers a more precise Sideral Time display on a sub-dial at 12 o’clock, as well as a power reserve indicator between 4 and 5 o’clock, and of course the solar time as well. What is perhaps most attractive about the Portuguese Sidérale Scafusia though, aesthetically speaking at least anyway, is the fact that IWC gives you the opportunity to personalize it with countless different combinations.


In total the choice of materials for the case, the five different colours for the dial, the various colours for the appliqués and straps and the material used for the straps, combine to offer over 200 different design options. And according to the brand, they are only too happy to honour special requests in the interests of exclusivity.

So, I guess the only question that remains is what will yours look like?

For more information on the IWC Portuguese Sidérale Scafusia please click here.

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