After the summer vacation last year, IWC launched a sophisticated watch called the Portuguese Sidérale Scafusia. It was successively released at the Torrena Observatory in Chile and the birthplace of this special watch in Schaffhausen, Switzerland. This watch is an important milestone in the development of IWC, marking the official entry of IWC into the ranks of astronomical watches capable of displaying the sky map. This watch not only has a lot of wonderful functions such as the stellar time, sunrise and sunset time and constant force tourbillon.
Since the Big Bang, the universe has been expanding at an alarming rate. But from the perspective of the earth, the familiar constellation has never changed from generation to generation. Many planets may be several light years or thousands of light years apart, but for us, the stars in the sky have always dotted the night sky and are constantly spinning on this large dome. Although we now know that the earth is actually spinning, it seems easier and more intuitive to imagine the stars spinning. Since the rotation axis of the earth passes through the two poles, if you are patient enough, you can observe the stars in the sky around the head to rotate a little counterclockwise at the North Pole. At this point, the North Star is stationary, and the farther the star is from the North Star, the longer the orbit.
Plane starry sky
The sky map displayed on the plane is likely to cause a certain degree of distortion, so when you do not have an iPhone at hand, a starry sky rotating map can effectively help you identify stars. Planar celestial maps (projecting a hemisphere onto a plane) are an old trick. As early as the 16th century, Arab scientists invented the rotatable star chart of the famous brass astrolabe, which can determine the night time by the position of the star.
When observing the night sky outdoors, you are actually in the center of a certain range formed by the horizontal lines where the stars rise and fall. On a flat celestial figure, the horizontal line is represented by an ellipse carved on a transparent disc, and below the disc is a rotatable celestial disc. As the celestial disk rotates, the stars rise from the horizontal line on the east and fall on the horizontal line on the west.
Stellar time is a measurement method used by navigators to determine time based on the height of stars. It is more constant than solar time, because the measurement is based on the actual time it takes for the earth to rotate 360 ° around an infinite point in space, the vernal equinox.
Time measurement based on spatial infinity
Stellar time is a measurement method used by navigators to determine time based on the height of stars. It is more constant than solar time because it is measured based on the actual time it takes for the earth to rotate 360 ° around the point of infinity in the space around the vernal equinox. Stellar days are about four minutes shorter than the average solar day. Similar to solar time, stellar time is endemic. In stellar time, noon is when the vernal equinox is directly above the local meridian.
The introduction of the astrolabe in Europe prompted the design of clocks to innovate new functions to display the position of celestial bodies. The most famous of these inventions is the astrarium invented by Giovanni Dondi in the 14th century. Although the original clocks have been lost, replicas have been made from the original notes and drawings, one of which was exhibited at the International Clock Museum in La Chaux-de-Fonds. In addition to the astrolabe, this timepiece is also equipped with five clock faces showing the orbit of the planet centered on the earth. Towers and church bells are also equipped with astrolabes, notable examples of which include bells on the Prague City Hall, Bern’s Zytglogge, and the Strasbourg Cathedral clock.
Collectors race to own celestial watches
Watches equipped with celestial figures first appeared in the 20th century, and wealthy Americans scrambled to own the most sophisticated Swiss watches. The entrepreneur James Ward Packard asked Swiss watch brand Patek Philippe to design a pocket watch for him that showed the night sky in his hometown of Ohio. Another famous example comparable to this is the Graves watch belonging to the New York financier Henry Graves Jr in 1933. This watch is equipped with 24 complex timekeeping functions. In 1989, the 150th Anniversary Calibre 89 designed by Patek Philippe surpassed the complexity of Graves. Calibre 89 has 33 complex features, including its ability to truly depict the northern sky in the northern hemisphere. In 2000, the company continued to launch the Star Calibre pocket watch with 21 complex functions. This pocket watch has a rotating celestial map that can display the moon position and profit and loss. This process has also been applied to Patek Philippe’s most complicated watch, Sky Moon. Tourbillon, and later Celestial watches can fully display the entire night sky.
Let’s take a look at the current celestial watches, starting with the oldest astrolabe watch:
Astrolabe Galileo Galilei by Ulysse Nardin
This outstanding watch is one of the trilogy of Ulysse Nardin astronomical timepieces in 1985. For the first time, the function of a large tower clock like Zytglogge was introduced into the watch. Ludwig Oechslin’s design not only brings people a beautiful starry sky, it is also said to be the most accurate. This watch can display the stellar time and the average solar time, but only high-brightness stars. The designer uses the traditional astrolabe style. The sky and sun hands on the dial rotate clockwise. The sun hands represent the day time and the specific position of the sun on the ecliptic. The moon hands represent the moon position and profit and loss. The Tianlong hands show the moon’s intersection and intersection The ecliptic noodles pass every 18.6 years, indicating a solar and lunar eclipse.
CK Astrolabium CKAL7766 by Christiaan van der Klaauw
As a member of the AHCI (Arts and Humanities Citation Index), Van der Klaauw lives in the Netherlands, designs clocks independently and is unique in astronomical functions. The astronomical watch on his astrolabe shows the positions of the brightest stars, the sun, the moon and the intersection of the moon. Under the hands and stars are ancient patterns of the astrolabe, showing people the vast night sky.
Vacheron Constantin’s Tour de l’ Ile
This watch is ranked as the most complicated watch, and the oval bezel on the dial shows people the bright starry sky of Geneva. Although there is no function to display the stellar time, it can display the time difference between the solar time and the mean time. Other complicated functions include dual time zone display, moon age and profit and loss, minute repeater, perpetual calendar, tourbillon, sunrise and sunset time, and power reserve display.
Patek Philippe ref. 5102PR Celestial
This elegant automatic watch can display the night sky of the northern hemisphere. This technology is derived from the design of Star Calibre and Sky Moon Tourbillon. The starry sky on the dial rotates counterclockwise, and the oval bezel representing the horizon shows the Geneva and same latitude regions Night sky. Although the speed of the moon and stars in the sky is different, its position on the dial can accurately reflect its position in the sky. A hidden device can also display the moon’s profit and loss. The two arrows on the dial indicate the positions of Sirius and the moon, respectively. By adjusting the arrows, you can set the readings of the moon and the stars.
Van Cleef & Arpels
This elegant and noble watch bears the same name as a Van Cleef & Arpels perfume, displaying a bright night sky with emeralds embellishment throughout the dial. The elliptical bezel shows the positions of the stars in the night sky of Paris. The astrolabe only rotates once a year, so the stars on the astrolabe are only at the position where they really belong at midnight of the day.
Officine Panerai’s L’ Astronomo Luminor 1950
Panerai released the most complex watch in the International Year of Astronomy in 2009-L’ Astronomo Luminor 1950. The night sky on the back of the watch rotates counterclockwise, and the elliptical bezel made of frosted glass displays the starry sky at a specific latitude. The specific position can be set by the user.
Jaeger-LeCoultre Master Grande Tradition
This masterpiece by Le Sentier is in the same style as the Sky Moon Tourbillon. The astronomical function of the watch is accurate and reliable, but its outstanding appearance is equally striking. The rotating tourbillon on the side of the dial controls the rotation of a part of the starry sky. This rotating structure is set on the vernal equinox and rotates counterclockwise with the star to display the star time on a 24-hour basis. The Sun combines them in a subtle way, rotating on a transparent disk in a 24-hour stellar system. Consistent with actual operation, the sun rotates counterclockwise around the North Star, but is about 1 degree / day slower than the star. Therefore, the zodiac calendar showing the date will catch up with the rotation speed of the sun. The sun should be driven by a perimeter wheel, otherwise its rotation will conflict with the tourbillon. Other complication features include a flying tourbillon, a silicon escape wheel and a minute repeater.
IWC’s Portuguese Sidérale Scafusia
The main complication of the tourbillon watch is the stellar hour display. The stellar hour of this watch is collectively displayed on the small 24-hour clock face in hours and minutes. However, the essence of this watch is the star map behind the watch. The 500 stars are connected to form a variety of constellation night sky. The stars rotate around the polar axis on each star day. The polarization filter changes the sky color of the celestial map at dawn and dusk every day. In addition, IWC also designed the Southern Hemisphere star map for customers in the Southern Hemisphere. New programs written by astrophysicist Ben Moore can adapt astronomical maps to everyone’s needs, so users living near the equator can see the most accurate and clear night sky in their hometown.
The hands on this astral chart indicate the star’s direction as opposed to the 24-hour clock. It is difficult to understand why the sun hand is rotated clockwise, which requires a separate time scale. If the same design as the Jaeger-LeCoultre watch is used, the sun hour hand rotates in the same direction as the star, then the sun hour hand can display the date, so that the ecliptic designed by Moore for the star chart makes sense. Nevertheless, IWC engineers have incorporated another practical astronomical feature-sunrise and sunset time, which also appears in different designs in watches designed by Patek Philippe, Vacheron Constantin and Audemars Piguet. These two times are indicated by two small red arrows pointing to the outer scale, and the cam of the pointer needs to be cut and installed according to customer needs.
Other complication features include a constant tourbillon, sunrise and sunset times, and a perpetual calendar that shows the number of days in the year, not just the date.