Trilogy Booklet for UN - with all graphics in low resolution
The Trilogy of Time
Astrolabium - Planetarium - Tellurium
by Marcus Hanke
How it all began …
In 1983 Rolf Schnyder bought the watch manufacturing company Ulysse Nardin, which at that time was in immediate danger of bankruptcy. Ulysse Nardin had a tradition of watch making since 1846 and was famous for its high-quality chronometers not only built for private use, but also as navigational instruments used by several navies. During the Seventies the company became one of the many victims of the quick advance in watch technology and production. Millions of cheaply produced, accurate quartz watches flooded the market. This left the traditional mechanical watch, which was manufactured in a long and time consuming process with a lot of work done by hand, barely a chance to survive.
Nevertheless, Rolf Schnyder was convinced that the production of high-class mechanical timepieces still had a future. He also knew, that his newly acquired company would need something really spectacular to reintroduce its name into the exclusive league of the world’s best watch manufacturers. During the search for this specialty, Rolf Schnyder visited the workshop of a well-known watchmaker in Lucerne, Switzerland: Jörg Spöring. There, he noticed an extraordinary wall clock featuring an astronomical dial, a so-called astrolabe. Upon asking, he learned from the master that his apprentice, a certain Ludwig Oechslin, had constructed this clock. When Mr. Schnyder finally met this apprentice, he immediately asked him if it would be possible to create an astrolabe as small as a wristwatch. “Who would be interested in buying it?” was Oechslin’s laconic answer.
This was the start of not only a steady friendship, but also of an extraordinary co-operation. One result of it is presented in this book.
The Trilogy of Time
The Trilogy of Time is also available as a limited set
Some Notes about the History of Astronomy
What Does Astronomy Have to Do With Measuring Time?
In fact, our common measuring of time is nothing more than the observation of basic astronomical events. What we call a ‘day’ is the time span during which the Earth rotates once around its axis. Very early already, mankind divided this span into shorter intervals, which made it possible to keep record of the time elapsed within a day. The time shown by our timepieces, be they worn on our wrists or hanging on the walls of our homes, is always the representation of a specific moment during that rotation of the Earth.
Since all watches are only a simple product of astronomy, it was logical that the two functions – observation of astronomical events and the measuring of certain time intervals – were combined into a single device. In the beginning these devices hardly could be identified as ‘clocks’: megalithic arrangements like those at Stonehenge in England and Carnac in France, or Egyptian and Mayan temples. All of these artifacts were erected for astronomical observations and calculations as well as being a place to celebrate.
The megalithic alignments of Carnac in Brittany served as religious site as well as astronomical observatory.
The connection of astronomy, time and religion always was a very tight one. The first people noticed that the Sun rises and disappears in more or less regular intervals, that the Moon changes its face also regularly, and that the stars seemingly kept their positions eternally. Therefore, those celestial bodies became symbols for divine activities, which determined all life on Earth. People came to the belief that Sun, Moon and stars even were gods themselves, who needed to be worshipped. It consequently became increasingly important to dedicate rituals, held at specific times, to the gods. The architectural framework for the rituals became an instrument to determine the important moments by means of optical signs. Only on one or two days in a year, for example, (mostly the equinoxes) would the sunrays reach a specially marked stone or spot. To maintain the gods’ favour it was indispensable to celebrate the rituals at the exact time, which put the power of time into the hands of priests, who kept it for thousands of years. Until today, the Christian holiday of Easter Sunday is determined by astronomy. It is the first Sunday after the first full moon in spring.
Not only religious celebrations were held, following the accurate observation of astronomical cycles, but also daily life was influenced by these events. In ancient Egypt, it was noticed that the annual flooding of the Nile started shortly after the bright star Sirius appeared in the sky for the first time of the year (July 20th). This event determined the whole cycle of sowing and harvesting and therefore, the Egyptian year started with the appearance of Sirius.
After the multitude of gods assigned to the celestial bodies were replaced with the belief in the one God, astronomical timepieces not only kept their importance to calculate the correct times for ceremonies, but they gained an additional didactic function. The observation of Sun, Moon and the planets brought forward the insight, that their movements followed certain rules, which themselves could only be the result of God’s planning and his creation of the universe.
The huge astronomic clocks built in the Middle Ages and located in the churches had the purpose of demonstrating to all spectators the magnificent apparatus of the universe in which the Earth and man were placed in the centre with the universe rotating around just as it was planned and executed by the will of God. Therefore, the study of the celestial bodies, and the exposition of astronomical clocks were a means to discover mankind’s place in the universal order of things. They were instruments of philosophy and religion, and even instruments of indoctrination.
The huge astronomic clock in the cathedral of Strasbourg, France, was built in 1572–74.
Given this importance, it is not astonishing that the clerical monopoly of time was soon challenged by the cities: During the 15th and 16th centuries, these had gained massive economic strength, and were eager to demonstrate their independence from the church. While the old church towers were a natural place to locate public clock displays, the magistrates of wealthy towns quickly erected their own clock towers. Huge astronomic clocks, such as the magnificent clocks in Padua (1434), Prague (1486), or Berne (1530) were placed in either the townhalls, or in dedicated clock-towers, and proved to the public, that the interpretation of the universe was not an entirely spiritual issue, left at the discretion of priests.
The astronomic clock at the town hall of Prague, Czech Republic (1486)
Views of the World
When we observe the Sun’s path in relation to the stellar sky during a year, it seems that the Sun rotates around the Earth, which is positioned in the centre of the universe. This conclusion was made very early and found its way into the old texts about the creation of the world. It was scientifically explained mainly by the Egyptian mathematician and astronomer Ptolemy during the 2nd century AD.
The geocentric view of the solar system as Ptolemy defined it.
His geocentric system of the universe was adopted by the Catholic Church and fiercely defended, even when scientific proof, that the Sun is the centre, around which the Earth is rotating, was brought forward by Nicolaus Copernicus in his book “De revolutionibus”, published in 1543. Consequently, Copernicus and other defenders of his heliocentric system ran into serious trouble with the Church. Galileo Galilei had to publicly retract his support of the Copernican theory. Giordano Bruno was even burnt on the stake by the Inquisition. Too far away was the new theory from the traditional dogma about the Earth’s position in the known universe. It seemed blasphemy to consider that God’s final and finest creation, mankind, was not the centre of the world.
The heliocentric or Copernican system.
Even when the heliocentric model finally was adopted, there were still too many apparent inconsistencies and contradictions. The movement of certain planets just did not follow the predictions, which were based on the assumption that all celestial bodies moved in perfect circles. The impression, that the universe was a gigantic automaton created by God, and followed strict divine laws, prevailed. Moreover, as a special privilege from God, man was enabled to use the same laws to recreate the universe in a small scale as astronomic automatons in mechanical clocks.
It was Johannes Kepler, who finally delivered a serious blow against this conception, when he proved that the planets moved along ellipses rather than perfect circles. Sir Isaac Newton, with his gravitational laws, demonstrated that so many different gravitational influences have an effect on the planets’ movements, and that it is merely impossible to predict them by means of strict and eternally valid formulas. Suddenly, it became meaningless to reproduce the universal movements by means of automatons, and the importance of the mechanical astronomical clocks as a means of scientific, as well religious demonstration and education quickly vanished.
Celestial Mechanics 101
Sun and Earth
The Rotation of the Earth
The Earth rotates around its own axis, causing the impression that the Sun rises in the morning, passes its zenith at noon and sets in the evening which is followed by a period of darkness, the night. This complete cycle is one day, the basic time interval which can be defined by astronomic events. In ancient times, the definition of the day had already been established as the period between two zeniths of the Sun. By means of a simple stick in the Earth, it was easy to determine that the Sun had reached its highest point, when the shadow cast by the stick had its shortest length. However, different cultures placed the beginning of a new day on different times, be it the sunrise, the sunset or the noon. In the Roman Empire, the day changed at midnight, which was a difficult issue, since no astronomical event helped to determine this exact time.
The possibility to count days alone was not enough though, and a more detailed subdivision was needed. This was achieved by dividing daylight and night into twelve hours each, totalling twenty-four hours per complete day. The twelve hour interval was already introduced in ancient times, since the number twelve was a sacred number in nearly every old culture. In Rome, the twelve daylight hours started at sunrise, the twelve nighttime hours at sunset. The apparent problem with this subdivision is that the Earth’s rotation axis is not at a right angle to its orbit around the Sun, but it is slanted some 23 degrees. This angle is responsible for the change of the seasons and the different lengths of light and dark periods during the year. Therefore, the old method to measure the daytime, the so-called ‘apparent solar time’, accepted different lengths of the hours. During winter, the twelve night-time hours were much longer than the twelve daytime hours, and vice versa during summer. Consequently, night and day hours varied in their lengths, between 75 and 44 minutes. Only at the two equinoxes did they last equally long, 60 minutes. It is clear that this system of measuring time implies differences as soon as the geographical location is changed. Due to the Earth’s rotation, places in the East experience sunrise and sunset earlier than those in the West, resulting in a considerable difference at larger distances. Since the average circle of social relations at that time was very small, caused by the lack of long range communication assets and fast means of transportation (around 1500, a journey from Venice to Lissabon lasted about 46 days!), this difference was hardly noticeable. The system of using the apparent solar time was convenient to use and easy to understand for all people, who normally did not possess clocks, but were well aware of sunrise and sunset as daytime constants.
One complete rotation of the Earth needs 23 hours and 56 minutes. Since the Earth in the meantime has moved along its path around the Sun, its angle of illumination has changed too, so the time span between noon A and noon B is four minutes longer.
The introduction of reliable mechanical clocks during the late 15th century made these flexible hour lengths problematic, since the hours they measured were all equally long. For that reason, the ‘mean solar time’ was introduced, then designated ‘Italian hours’, after the region of their first general use. This way of time measurement was independent from sunrise and sunset, and is still used today. So the clocks first had to ‘invent’ the regular hours before they could display them. For the people this was a drastic change and made necessary the use of tables and sophisticated instruments (astrolabes for example) to translate the hours shown in mean solar time into the traditional apparent solar time.
Nevertheless, the definition of a day being the time between two noons is still problematic, since it does not reflect the true rotational period of the Earth.
If a certain point on Earth’s surface is marked, and the time span needed for one complete 360 degrees-rotation of this point is measured, it is about four minutes shorter than twenty-four hours. However, since the Earth itself has travelled a certain distance on its orbit around the Sun during the 24-hour-period, it has to rotate a bit more than 360 degrees until the same point has noon again. The time needed for a true 360 degree rotation of the Earth is called a “stellar day”.
The Movement of the Earth Around the Sun
By observing the stars which the Earth seems to pass once a year, its path around the Sun can be easily traced.
However, since the observations of our solar system are not made from a virtual fixed point somewhere far above the system, we cannot recognize the Earth’s movement itself. Our observing location is positioned on the Earth, which for us, of course, seems to stand still. From our viewpoint, it is the Sun that apparently is moving through the sky. This is the reason why the theory of the geocentric universe seemed so logical at its time.
While the Earth rotates around the Sun, the view of the sky from the Earth (red arrow) is constantly changing.
It is easy to understand the principle, if one imagines a ride on those merry-go-rounds which can be found on children’s playgrounds. As long as the spectator is standing aside and looks at the turning disc, he realizes that the children on the disc are rotating around its central axis. But if he himself steps onto the disc and concentrates on the apparent position of the rotation axis relative to the surroundings of the merry-go-round, he can come to the conclusion that the axis is rotating around his own position.
The plane described by the Earth’s rotation around the Sun is called the ecliptic. With the exception of Pluto, all other planets in the solar system also are moving within only a few degrees of the ecliptic. From the Earth’s viewpoint, the Sun seems to travel around the Earth on the ecliptic, which itself meets the illusional sphere of stars behind the Sun. Of course we know very well, that the stars we can see, are suns or even galaxies with different distances to our solar system. For observation purposes, though, one has to think of the distant stars as being ‘glued’ onto a huge sphere, which is the outer limit of our little imagined universe. The Sun’s journey during the year can be measured by its position relative to several distinct stellar constellations dispersed along the ecliptic – the well-known twelve signs of the zodiac (again the sacred number twelve was chosen already in ancient times). These signs of the zodiac are somehow like a canvas, on which the progression of the year can be observed. The twelve signs correspond to twelve months subdividing the year, although today, its limits do not correspond exactly with the beginning and end of the months. It is also possible to check all the other planets’ movements against the zodiac in the ecliptic.
Seen from the Earth, the rotation around the Sun is perceived the other way round – as if the Sun moves around the Earth; the plane of the rotation is the ecliptic, while the background of the stars is designated the celestial sphere, which has the Earth in its centre.
Unfortunately, the ecliptic is not identical with the equatorial line of the Earth, since its rotational axis is not at a right angle with the ecliptic. If the plane of the Earth’s equator is enlarged, until it meets the sphere of the stars, you get a line angled at 23 degrees to the ecliptic, the celestial equator.
The celestial equator is the projection of the Earth’s equator, which is angled about 23 degrees to the ecliptic, due to the inclination of the rotational axis. Consequently, also the poles of the celestial sphere are inclined.
Now we have to combine both movements discussed, the rotation of the Earth itself and its circle around the Sun, to realize that, due to that angled axis, we cannot see the ecliptic the same way all the time. Earth is rotating us into a different angle every day, therefore there are many stellar constellations or objects we cannot observe permanently. Stars like Sirius or Rigel seem to rise at a certain time of the year, and after a period of observability, they disappear again. This seemingly complicated pattern of movements could be used to the advantage, either to determine an exact date or for navigational purposes.
But not only astronomical observations are influenced by the difference between the ecliptic and the equator. Far more important for our daily life is the effect of the changing amount of sunlight received by the different parts of the Earth’s surface during a year. This results in the four different seasons: spring, summer, autumn and winter. Due to the angle of Earth’s rotational axis, the two hemispheres are differently illuminated. If there is summer in the northern hemisphere, the North Pole is positioned in the illuminated part of the Earth all the time, resulting in the polar summer, with no nightfall for half a year. The daylight periods are longer than the nights. At the same time, the South Pole is shrouded in darkness for half a year. Then it is winter on the southern hemisphere, and there the nights are longer than the days. Only twice a year, on March 21st and September 23rd, night and day are equally long on all the Earth. These two dates, where the lines of the ecliptic and the equator meet, are called the equinoxes and mark the beginning of spring and autumn. Two other dates mark the beginning of summer (June 21st) and winter (December 22nd). The former has the longest daylight period on the northern hemisphere. Thereafter, the daylight times decrease, while the latter has the longest night, with the days becoming longer again.
The rotation cycles of the Earth around the Sun impose a serious problem to our calendars. Unfortunately, the Earth does not need 365 full rotations (days) to complete one cycle, but nearly a quarter of a day longer than that. Therefore, every year includes an unfinished fraction of a day, which after four years is summed up to a bit less than one day. Since our calendar systems are based on complete days, they have to correct the mistake by the insertion of an additional day (February 29th) in the leap years. This manipulation again is slightly larger than necessary, therefore some other corrective interventions have to be made in the calendar every hundred, and again every four hundred years. But due to the gravitational effects of all the planetary masses in the solar system, the Earth is accelerating a little, so that the years become shorter, albeit at a minimal rate.
Earth and Moon
The Phases of the Moon
The lunar phases are the result of the changing illumination by the Sun, which has its reason in the rotation of the Moon around the Earth.
An 18th century illustration shows the various phases of the Moon.
On its path, the Moon has a position between the Sun and the Earth once, so we only see its shadowed side, which of course results in seeing nothing of the Moon at all. This phase is the new moon. After having orbited to the opposite side of the Earth, the Moon is fully back-lit by the Sun when observed from the Earth; this is full moon. Between these two phases, the Moon is waxing or waning.
The conjunction of Earth and its moon are shown in this picture from the Galileo orbiter in 1992.
The period between two same phases is 29 days, 12 hours, 44 minutes and 2.9 seconds, which is also called the synodic month. Again, similar to the definition of a day, based on the rotation of the Earth, the lunar phases do not accurately correspond with the real rotation of the Moon.
To complete a 360 degree circle around the Earth, the Moon only needs 27 days, 7 hours, 43 minutes and 11.5 seconds (sidereal month), but in the meantime, the whole Earth–Moon system itself has moved on its path around the Sun, and the angle of illumination has changed too.
Due to the changed angle of illumination, the time span between two new moons (synodic month) is longer than the period of one complete rotation of the Moon around the Earth (sidereal month).
Due to gravitational effects, the mean distance between Earth and Moon is increasing, so the time for a rotation around the Earth also becomes slightly longer. This is another proof against the old perception of the universe being a rule-dictated machine.
The different layers of the Sun’s corona, as seen during the total eclipse on August 11th, 1999
Solar and Lunar Eclipses
When the Moon is positioned between the Sun and the Earth, it casts a shadow onto the latter, blocking the sunrays from the Earth’s surface and causing a solar eclipse. Since the Moon is not large, its shadow is limited to a restricted zone. This core shadow, called umbra, has a diameter not larger than 200 to 300 kilometres. Observed from outside the umbra, the eclipse is only a partial one, since the Moon’s disc seen from the Earth is just large enough to barely cover the Sun. But not every eclipse of the Sun is total, in fact only a small minority are. The others are either partial or ring shaped. The latter is the case when the distance of the Moon from the Earth is not small enough for the moon disc’s shadow to cover the Sun entirely.
Total eclipses of the sun, as visible on the Earth 1999 – 2020
As long as the Moon’s orbit passes the ecliptic on nodes similar to nodes A, the Moon will stand clear of the Earth’s shadow at full moon, and the Moon’s shadow will miss the Earth at new moon. But when the nodes move to position B, the Moon is very near the ecliptic, and at new moon its shadow is cast on Earth’s surface – a solar eclipse occurs. At full moon however, the Moon enters the shadow of the Earth, resulting in a lunar eclipse.
Anybody who has the rare opportunity to see a total eclipse will never forget the experience. Within minutes, the Sun disappears and it becomes as dark as a normal moonlit night. Temperature drops within seconds and nature goes to sleep. Since the Moon blocks the bright disc of the Sun, one can see the corona – a belt of hot gas which is normally outshined by the Sun.
Another type of eclipse happens if the Earth is blocking the sunlight from the Moon passing behind it. The shadow cast by the Earth is darkening the full moon and, since the Earth’s shadow is so much larger than its satellite, the lunar eclipse can be observed from everywhere on the night side of the Earth. Due to the refraction of the sunlight in Earth’s upper atmosphere, the Moon appears in a fiery red shortly before it disappears in the earth shadow. The same fascinating view is experienced again when the Moon leaves the shadow.
Now one might ask, why the Moon’s path around the Earth does not cause a solar and a lunar eclipse every month, since at every full moon the Earth is located between Sun and Moon, and at every new moon the Moon is between Earth and Sun. If the orbit of the Moon would lie on the same plane as the ecliptic, this would indeed be the case. However, the lunar orbit is angled approximately 5 degrees to the ecliptic, so normally the Moon passes too far above or beneath the Sun or the Earth's shadow to cause an eclipse. The lunar orbit is meeting the ecliptic in two nodes, which (to complicate things even further) themselves are slowly moving. Only if the Moon is near one of the two nodes, an can eclipse take place – if the Sun–Earth–Moon constellation is correct, of course.
Creating masterpieces
The Creator: Ludwig Oechslin
Born in 1952 in Italy, Ludwig Oechslin visited schools in the German-speaking part of Switzerland, before he started his academic career in 1972. Then he began his classical studies (a combination of archaeology, ancient history, Greek and Latin) as well as history, history of arts and philosophy at the university of Basel, where he graduated in 1976.
Ludwig Oechslin in his private atelier
If one takes into account his later career and fame as one of the world’s leading personalities in watch making, it is quite ironic that Oechslin never had worn a watch before, since his day was dictated by the large school clocks. However, when attending classes at university, his schedule became more densely packed. But above all, it had to be individually organized, therefore the purchase of a watch became indispensable. While visiting a watch shop, he took a special pocket watch into his hands – a repeater. The complexity of the movement, and especially the chiming mechanism, fascinated him at once. Unfortunately, he could not afford the watch, but for a man like him, this was not a reason to give up. “Then I’ll build my own!“ was the logical conclusion he drew from his encounter with the watch.
But before, his growing dissatisfaction with the ivory-tower-theory taught at the university urged him to look for a profession in which he could use his own hands practically, as well be creative. Now it was clear for him that he wanted to become a watchmaker. At the age of 24, it was not easy to find a master willing to accept him for apprenticeship. Finally Jörg Spöring, a well-known watchmaker and restorer of antique clocks, took Ludwig Oechslin under his wings.
After a short time, Oechslin had his first intense contact with an old astronomic clock. He was sent to the Vatican to repair and restore the Farnesian Clock, an astronomical clock more than 250 years old and of unequalled complexity. Not only did he repair the timepiece, he also remanufactured a large share of the parts and studied the clock’s functions, what kept him busy for years. The results intrigued him, and he wanted to know more about the people who created such clocks, their thoughts, and the scientific implications behind them. Upon his return from Rome in 1982, he started additional studies in the disciplines astronomy, philosophy, and history of science (theoretical physics) at the university of Bern, graduating as a Doctor in 1983, after having published his dissertation about the clock as a cosmological model. As a side note it should be said that the publication of Dr. Oechslin’s doctoral thesis had to be postponed, because the data therein could possibly have interfered with the patenting procedure of the Astrolabium.
Within the next dozen years, Oechslin became an internationally appraised expert on astronomical timepieces from the 16th to the 18th century, travelling around Europe to restore and study old clocks. Besides that, he continued of course with his training as a watchmaker, receiving his diploma in 1984 and finally became a master watchmaker in 1993. Both his practical training as a watchmaker, and his academic career went hand in hand. The latter reached a height when he got his license to teach at universities in 1995 (a longish procedure traditional with Central European universities, the “habilitation”, necessitates the publishing of a voluminous scholarly work as well as giving several lectures before the “venia legendi”, the license to teach, is accorded). He subsequently joined the faculty of the Swiss Federal Institute of Technology in Zurich – one of the best-known technical universities in the world, holding lectures about astronomy, cultural history and cosmology.
Ludwig Oechslin’s scientific excellence, and his fame as one of world’s most innovative watchmakers, were honoured, when in 2001, the city council of La Chaux-de-Fonds offered him the position as the curator-director of the International Watch Museum, the most complete and renown horological collection in the world.
Ludwig Oechslin and the Trilogy of Time
Soon after he was commissioned with the development of the Astrolabium, Oechslin completed his prototype in 1983. Two years later, the watch was presented to the public during the Basel watch fair, and astonished both watch lovers and watchmakers. Never before had an astronomic mechanism of similar complexity been integrated into a small wristwatch. The Astrolabium was immediately adopted into the famous Guinness Book of Records, as well as integrated into the permanent collections of several museums worldwide. However, this success was only the beginning and assured Schnyder and Oechslin to continue building Ulysse Nardin’s reputation as one of the best watch manufacturing companies in the world. From the very beginning already, Oechslin had planned to embed the Astrolabium into a system of astronomical watches, in order to present them together as a small cosmological model. Only three years later, in 1988, Ulysse Nardin presented the next masterpiece developed by him: the Planetarium. And again the public looked with awe at the new marvel, which integrated the planets’ movements into a tiny model, small enough to be worn on the wrist. This watch, too, immediately found its way into the Guinness Book of Records, and once again collectors and museums were quick to add it to their inventory.
Ludwig Oechslin in his atelier at Ulysse Nardin
But the final coup had yet to follow. In 1992 the piece completing the Trilogy of Time was unveiled, the Tellurium, showing a depiction of the Earth–Moon–Sun system together with the changing illumination of the Earth’s globe by the Sun. The “Trilogy of Time” as a whole was the impressive demonstration that Ulysse Nardin belonged to the most innovative watch manufactories in the world, less than ten years after Rolf Schnyder had saved it from imminent bankruptcy. Moreover, it proved what the correct mixture of idealism, capability and economic commitment can accomplish. Ulysse Nardin had found its path of individualism, and raised its position above and away from anonymous mass products.
[Picture: L. Oechslin working on a watch (from the brochure “The Master Timekeepers”, page 6)]
After the completion of the astronomic Trilogy Ludwig Oechslin directed his attention to other, this time more “earthly”, projects. He designed the first simple-to-use and reliable mechanism for adjusting a watch to different time zones, even backwards over the date line. He also created the first mechanical perpetual calendar, which can be adjusted forward as well as backward simply by means of a single crown, and in 1999 even combined it with an additional GMT-mechanism.
[Picture of Perpetual GMT from the catalogue]
Only a few years later, in 2001, Ulysse Nardin stunned the horological world with Ludwig’s idea of a ‘simple’ watch: The astonishing Freak, a seven-days-caroussel tourbillon, in which the two movement bridges themselves serve as ‘hands’ to display the time. Heart of the Freak is the new dual direct escapement, which makes use of wheels made from silicone.
[Picture of Freak from the catalogue]
2003 brought another apex of Ludwig Oechslin’s genius, when Ulysse Nardin presented the Sonata, world’s first mechanical alarm watch, which enables its wearer to set the alarm over 24 hours in advance, and see the remaining time until the alarm gets off on a unique count-down display. This automatically takes into account changes of the current time zone, via the integrated GMT mechanism. The development of this watch needed seven years in total.
Now let us recall that day when Ludwig Oechslin found a repeater watch and decided to become a watchmaker to build one himself. He never built it. As soon as he was able enough to construct and assemble such a watch, he also realized that it was nothing new. Countless watchmakers before him had built repeaters and brought them to perfection. However, what continues to intrigue him is the challenge of making something completely new, something never seen before in a watch, and to this he dedicates his creative energy enriching the horological world with amazing masterpieces.
Understanding the Philosophy Behind the Trilogy of Time
The fact, that Ludwig Oechslin chose the three astronomical mechanisms astrolabe, planetarium and tellurium for the Trilogy of Time was not accidental, since these types of automatons present an interpretation of the world and the universe from a scientific point of view. More than that, they also express a spiritual model of the cosmos and of our little world in it.
The important historical role of astronomical clocks in religion and even policy has been pointed out in the previous chapters. Additionally, these automatons served the purpose to intensify the people’s contact with their astronomical environment. During all time, people’s days were dictated by astronomy, be it the course of the Sun in the sky, be it the Moon and its phases, or the seasons which resulted from the Earth’s path around the Sun. Astronomical clocks demonstrated to their spectators, how God had made these things to work, and why everything is happening according to his will. Besides the religious aspects, all the observations of the sky and the reconstruction of its system were only made in order to better understand Earth and its place therein. This means that the primary motivation behind the studies was the Earth itself.
Today we seemingly have lost the contact to our own planet. On the one hand we are chasing for seconds or even for fractions of them, sitting in artificially lighted offices and halls. Electric lighting has driven back the night’s darkness. If you want to study the sky at night thoroughly, you have to search for a place somewhere in the desert, because our habitations spill too much light into our atmosphere. We have been decoupled from the astronomical events which left their marks on our ancestors’ everyday life. We leave home for work without respect if the Sun has already risen or not. When it reaches its zenith at noon, we are sitting at tables in the light of electric bulbs and the setting of the Sun does not leave any impression on us, if we are not on a seaside beach during our holidays. The lunar phases have lost their former importance on our lives too. Only the seasons are somewhat still relevant for heating costs and the weather forecast.
On the other hand, we have learned so much about space and the planets that we think of the Earth being not more than a tiny speck of dust somewhere on the rim of our galaxy. With our attention focussed on objects so far away, we often overlook the importance our own planet has for us and our future.
By means of the Trilogy of Time, Ludwig Oechslin tries to increase our sensitivity for the things happening in the sky, so that we become aware again of our place and our responsibility for it. Seconds are not the relevant scale here, and not even the date of the days, which are but an arbitrary subdivision of a year. What count are the movements of the Sun, the Moon, the planets, and of course the Earth, which is in the centre of all three watches.
The three watches can be understood as milestones of a long voyage. It starts from a point outside the solar system, from where the spectator can see the Earth as well as most of the planets. This is the scenery of the Planetarium. As he gets closer, the Earth’s globe fills his sight, together with the Moon orbiting around it. He can observe the Earth’s rotation as well as the seasonal change of its illumination, all of which is displayed on the Tellurium. Finally, the traveller has arrived on Earth’s surface, directing his view back to where he came from – the stars which wander over the Astrolabium’s dial.
The “Türler Clock – Model of Cosmos” is installed in Zurich, Paradeplatz
However, Oechslin’s model of the cosmos still was not complete. A final and spectacular apex was to follow when he integrated all the Trilogy’s information and much more into the large and impressive “Türler Clock – The Model of Cosmos”, unveiled in 1995 and installed in Türler’s shop in Zurich, Switzerland. His former master, Jörg Spöring, built this large astronomical clock following Oechslin’s plans and calculations.
While all three watches of the Trilogy display the Earth as their crucial point, be it as the observational base in the Astrolabium, as the fixed part of the Planetarium, or the rotating centre of the Tellurium, the Türler clock focusses on other, sometimes more traditional aspects of astronomical automatons. Its planetarium shows all the solar system’s planets, even Pluto, in their movements around the Sun. The Earth is but a part of that eternal dance. The Tellurium, too, does not have the Earth in its centre, but displays Earth and Moon moving around the central Sun. The most impressive part of the clock, however, is a model of the Earth’s globe embedded into a crystal sphere with golden stars on it, symbolizing the celestial sphere. This sphere rotates incredibly slowly around the globe, once in 25,794 years (a so-called platonic year).
Ludwig Oechslin’s vision of the cosmos, as expressed in the timepieces of the Trilogy of Time, cannot be complete without the magnificent Türler clock, one of the most complex clocks in the world. Unfortunately, even Oechslin’s genius is not able to stuff the great globe with its celestial sphere into something as small as a wristwatch!
Technological Challenges
The realization of the Trilogy pieces in the first instance was faced with big technological problems. By means of conventional watch making technology it was believed impossible to manufacture mechanisms like those introduced with Astrolabium, Planetarium and Tellurium. The key was hidden in that old astronomical automaton studied and restored by Oechslin in the Vatican: the Farnesian clock. When he took it apart, Oechslin realized that most of its displays were driven by means of layered epicyclic gear systems.
Rotation of epicyclic wheels
Epicyclic is a wheel mounted eccentrically on another wheel, moving around this centre wheel while turning itself, too. Sounds complicated? Well, it certainly is. Oechslin knew that there must be some mathematical formulas behind that mechanism, but was unable to find any reference in the old books. Therefore he faced the challenge and completely recreated the analytical and mathematical model necessary to calculate the positioning, dimensions and number of teeth for all the gear wheels. This enabled him to remanufacture the damaged parts of the Farnesian clock.
Once he had developed the mathematics, he was able to transfer the system into a small wristwatch – theoretically. However, here he encountered new problems from the material side. A large astronomical museum clock is very unlikely to be moved, let alone to be subjected to heat, cold, shocks, and similar hazards. Therefore, the material stability or its mass are not of extreme importance. A wristwatch, on the other hand is accompanying its wearer nearly everywhere, and of course has to resist all those smaller and larger hits, bumps and watering incidents, which normally happen every day. The mechanisms employed in the Trilogy watches are so delicately adjusted and calculated that any maladjustment due to a shock could cause the watch’s astrological displays become inaccurate. Main reason for concern was the large size of the rings and discs used for the astronomical indications. Were they made from conventional materials, such as brass or silver, they would have been too heavy, with their mass inertia putting too much strain on the wheelwork, in case of a sudden bump.
The problem’s solution was found in aerospace technology, where new alloys, that were ultra light and highly resistant against shock or temperature changes at the same time, had been developed. The watch parts made from these alloys are so light, that they even float on water and still are as tough as parts made from brass or steel.
[Picture: Month/zodiac ring (Brochure: “The Master Timekeepers”, page 9)]
Additionally, there are hundreds of tiny balls with a diameter as small as 0.5 millimetres, on which the astronomical gears are running. They had to be found in a specialized industry, before they could be implemented into the Astrolabium’s system. Finally, the whole system had reached an unbelievable degree of accuracy. The calculation base of the Astrolabium’s mechanism leads to an error of one day after 144,000 years! This is far more accurate than the solar system itself because of gravitational influences. The Earth, Moon and the other planets will have changed their orbits and rotation times considerably in that time span.
The Planetarium’s unique multi-disc-based display also could be mastered only with new ideas. There, the fixed location of the Earth helped, since it was possible to locate all the gearing beneath its ring. And finally, there is the Tellurium, which, while looking even simple when compared with its two predecessors, confronted its creators with a constructional problem especially difficult to solve: The thin flexible string, marking the demarcation line between the illuminated and the dark side of the Earth, has to be trained by a gear, ensuring that it always bends correctly during the changing seasons of the year. At the same time, the wear on the gear had to be kept on a minimum, so that the Tellurium works flawlessly for a very long time. Finally, Ludwig Oechslin’s genius and the ingenuity of Ulysse Nardin’s technicians overcame all problems, presenting unique timepieces to the horological world.
But the Trilogy watches have not been made to be seen as mere pieces of jewellery and kept locked away in a safe. On the contrary, they should be used everyday, and they have been prepared to fulfil that task. The setting and adjusting of the different indications has been simplified so much that it is possible to execute all necessary changes by means of the crown only, respectively by the crown and one additional pusher in the Tellurium. To make possible that simplification, new ways to protect the delicate mechanisms behind the dial had to be developed. Special friction clutch systems prevent the gearing systems from being damaged when the quick correction function is used to move the indications forward or even backward.
The watches’ gold or platinum cases are watertight, and the hour and minute hands are treated with luminous mass (with the exception of the new limited set edition in platinum) so that the time is easily legible even under adverse light conditions. After all, Ludwig Oechslin’s philosophy of usability and simplicity influenced the Trilogy pieces’ design more than just superficially, in spite of their apparent complexity as astronomical timepieces.
Craftsmanship
Besides the technical side of the astronomical mechanisms, the Trilogy pieces are also examples of the finest craftsmanship when it comes to decoration: The gilt movements are finely engraved and chased by the most able masters of this profession.
The rotors of the self-winding mechanisms are painstakingly skeletonized to show the anchor logo of Ulysse Nardin, while the loss of mass is compensated by massive gold as rotor material.
[Picture: Mounting of Astrolabium rotor (from the brochure The Master Timekeepers, page 9)]
The use of precious materials is continued on the other parts of the Trilogy watches. A limited series of only 65 Planetaria even has its planetary rings made from a meteorite which Admiral Peary brought back from his polar expedition in 1897.
[Picture: Meteorite Planetarium from the book History in Time, page 77]
Enamel Cloisonné
Ulysse Nardin became famous not only for technical innovations, but also for reviving old and seemingly forgotten arts, the most beautiful example being the cloisonné enamelling. This fine enamel technique had its greatest period from the 10th to the 12th century, especially in the Byzantine Empire. In addition, China developed a rich culture of cloisonné.
[Picture: UN cloisonné dial - Jungle Repeater or San Marco]
Enamel is a comparatively soft glass, a compound of silica, red lead and soda or potash. These materials melt together, resulting in a nearly colourless glass with a slightly bluish tint. The agents responsible for the bright and glowing colours are metallic oxides, which are introduced into the molten glass. Brilliance of the enamel depends on the right combination of all components and the steady temperature in the melting furnace. The colours of the enamel are achieved mostly in a change of proportion of the different components rather than by a change in the oxides’ quantity. The heated enamel finally is allowed to solidify into cakes of about 10 centimetres diameter, which for use has to be powdered in a mortar.
[Picture: Powdering enamel, from the book History in Time, page 116]
In a series of washings, all floury particles are removed from the powder, which then is applied as a wet paste to the metal base cleaned and prepared by acids. The baking in the furnace afterwards is fusing the enamel with the metal.
[Picture: Baking enamel dials, from the book History in Time, page 116]
While the ‘conventional’ enamelling already is a very difficult procedure, making a work of art by means of cloisonné is even more complicated, and consequently is mastered only by very few artists today.
In this technique, an extremely thin gold wire with a thickness of only 0.07 millimetres and a height of one millimetre, is bent by hand with two pairs of pincers to follow the wanted contours. In the example of the Tellurium’s Earth, these contours follow the continents and the major islands, on a disc not more than two centimetres in diameter. The smaller the motif, the more difficult it is to bend the wire into the right shape.
[Picture: Bending the cloisons, from the brochure Baked enamel and enamel cloisonné – an old art rediscovered, page 4]
By means of vegetable glue the wires are glued to the dial, which then is baked at 840 degrees Celsius, until the glue has solidified and the wires are firmly attached to the dial.
[Picture: Gluing the wires to the dial, from the brochure Baked enamel and enamel cloisonné – an old art rediscovered, page 5]
A decidedly non-high-tech instrument is used to apply the enamel paste into the different cells: a goose quill, which experience has proven to be the best tool for that delicate process.
[Picture: Filling the cells with enamel, from the book History in Time, page 119 (shows Mayflower dial)]
The wire cells prevent the colours from mergeing into one another, which would make it impossible to recognize the continents afterwards. However, this blurring effect can also be welcome. This is how the fine variations of green, yellow and brown continental zones are accomplished on the Tellurium dial.
Four to five layers of enamel are applied to the dial and each one is then baked in the furnace. The multi-layering is necessary to obtain the glossy and even glowing colour of the enamel after polishing. Additionally, the uneven thickness of the differently coloured continents and oceans can be levelled as well.
After this process, another piece of delicate handwork is necessary; the reduction of the gold wires jutting out from the enamel surface. Extreme care is indispensable when polishing the wires, until they are completely flush with the enamel, and a final smoothening procedure brings out the deep shine and glow of the enamel dial.
[Picture: Dial before and after polishing, from the brochure Tellurium, page 12]
Fifty-four processes, twelve baking operations, and more than fifty working hours are needed to transform a drafted sketch on a small metal disc into a uniquely designed work of art. This includes the exact positioning of the gold wires, the application of the enamel colours to the cells and the filing and final polishing. All of this work can be destroyed within seconds by something as simple as a heating problem in the furnace.
The enamel dial makes the Tellurium even more unique. Since gold wires cannot show the exact same contours every time, every Tellurium is different from the other. The colours melt into one another and vary from one dial to dial thus the owner of a Tellurium can be assured that nobody else on the world wearing the same watch.
Using the Trilogy
The Astrolabium
Already in ancient Greece, navigators used astrolabes to calculate time and position by means of measuring the exact elevation angle of stars, planets and the Sun over the horizon. The observed data could be transferred to the astrolabe, which again presented the desired result on several scales. For astronomers, the astrolabe served as a mobile star chart, but it could also be used as a clock, a geographical tool, a surveillance instrument or as means of converting time measurements. Because of such features, the astrolabe can be regarded as a kind of rudimentary analogue computer.
It became extremely popular in the Middle Ages, but was replaced by the even more versatile sextant in its navigational field of use, and by portable mechanical clocks that measured time. However, for very specific astronomical tasks, astrolabes – albeit much more modern in appearance than the classic ones – are still used today.
If one were to compare Ludwig Oechslin’s Astrolabium with its medieval predecessors, there is one difference that might be noticed immediately. The classic astrolabes were used “the other way round”, which means, that a metal ruler (called alidade) was used to sight certain objects in the sky, and then the alidade’s position was transferred onto several scales found on the astrolabe’s back side. These scales then displayed the current time together with other astronomical information. However, the setting on the back also influenced the display on the astrolabe’s front, where an open-pattern disc (the rete) with a “map” of important stars rotated on the heavy base plate (the mater), engraved with a network of lines representing celestial co-ordinates.
Therefore, this traditional astrolabe served two different purposes: to observe and to display. Ulysse Nardin’s Astrolabium concentrates on the latter aspect. It only displays astronomical information, without offering the ability to actually observe celestial bodies. This is of course logical, since a wristwatch is too small an object to serve as a solid base for optical observations. And additionally, the main purpose of the observation – to determine the correct time – has become needless, since an accurate and reliable watch movement delivers the exact time, twenty-four hours a day.
In that respect, the Astrolabium watch is not new. Since the time when reliable mechanical clock movements were available, astrolabe functions have been coupled with them. These automatons should simplify the complicated process of reproducing the movements of the Sun, the Moon and the fixed stars. Big clocks with astrolabe dials, mostly installed in public places, have been known since the 14th century, and it was one of these clocks, the 17th century Farnesian clock, which delivered Ludwig Oechslin the experience and knowledge needed to miniaturise the complex mechanisms, until they fit into a wristwatch. This was the true innovation. Never before had a universe with Sun, Moon and stars been packed into such a small case.
Interpreting the Astrolabium
The core of every astrolabe, and therefore Ulysse Nardin’s Astrolabium, too, is a planispheric projection of the stellar sky above the observer. The main difficulty in understanding and interpreting this depiction, is that it is very difficult to reduce a three-dimensional space to the two dimensions of a watch dial. The same problem occurs, when the world’s geography is represented on a two-dimensional map, and we are all familiar with the somewhat distorted appearance the Earth has in a printed world map. In our case, the Astrolabium’s dial, corresponding with the mater of old astrolabes, is a projection of a semi-sphere that extends from the observer to its centre. The visible horizon is a circle stretching around the observer, and the celestial objects (stars and planets) seem to be fixed on a sphere stretching upward from the horizon. Since the Earth is blocking the observer’s sight downward, only the upper half of the sphere can be seen.
Once this concept is understood, the interpretation of data indicated by the Astrolabium’s dial is easy. It is also clear, that each observer on the Earth has an individual sphere stretching around him, and the location of celestial objects in relation to this sphere depends on his position on the Earth’s globe. For instance, if the observer stands on the North Pole, the Polar Star would be directly above his head, but from the equator, the Polar Star is observable at the horizon. Therefore, the Astrolabium can only be used properly, if it is “calibrated” to the observer’s position on the globe. As far as the latitudinal (north–south) position is concerned, this must be done during the manufacturing process, since the gridlines printed on the dial (or mater) change depending on whether the observer is located more northwards or more southwards on the Earth.
Every location on Earth has its own horizon, with its individual celestial sphere stretching above it. While the Earth continues rotating, the angle of the ecliptic towards the sphere of the visible sky changes constantly.
The longitudinal (east–west) position of the observer is important because of the differences in time: Locations in the East experience the sun rising before other locations more in the West. This difference can be taken into account by moving the sun hand forward or backward (see in the chapter: Setting the Astrolabium).
Reading the Legal/Normal Time
The hour and minute hands indicate the legal (or just ‘normal’) time, which is valid at the user’s current location, according to the appropriate time zone. Both are covered with luminous mass to make them visible at night (except the limited series platinum Astrolabium). On the bezel there are engraved Roman numerals, from I to XII, which in combination with the aforementioned hands show the current time. During daylight saving time (DST), the hour hand has to be advanced an hour.
In this example it is 10.10 legal time, but about 10.55 solar or local time.
Reading the Local/Solar Time
We know that any location in the East experiences sunrise or noon earlier than a location in the West. This is the result of Earth’s rotation. We also know that one complete rotation of 360 degrees needs a period of one day (24 hours). Therefore, the rotation of only one-degree needs a 360th fraction of one day to complete, this fraction being four minutes long. Consequently, a place located only one degree further west from another place, experiences sunrise and noon four minutes later than that previous spot.
Today we are used to our system of time zones, and therefore involuntarily think that all places in the same time zone must have noon at the same time. But let us remember how this time zone system came into being: As we have learned before, in earlier times every place had its own time indicated by large sundials. When the shadow cast by the sundial’s rod had its shortest length, it was noon. This tradition was kept, even after mechanical clocks replaced the old sundials. In every day life, the differences in time between the towns were not a serious problem, because travelling was very slow, so practical consequences were negligible. But in the 19th century, with the opening of the first transcontinental railway line in the United States, rapid transportation became possible and common, and suddenly the problem of time differences was acute: How could anyone co-ordinate a railway timetable, when every single station had its own time?
In 1884, a Canadian railway planner and engineer, Sir Sandford Fleming, found the logical solution. He simply divided the Earth’s globe into twenty-four longitudinal zones (stretching from north to south), 15 degrees apart, starting with the prime meridian at Greenwich, England (Greenwich Mean Time, GMT). Within each zone there should be the same time. This system is the base of our modern communication and transportation, but we should not forget that it is a man-made, voluntary system, which does take into account the factual rotation of the Earth only roughly. An example might illustrate the problem:
Both, Budapest in Hungary and Brest in France, share the same time zone (GMT +1), but their geographical locations are twenty-three degrees apart. Since the standard for one time zone is 15 degrees, the two towns should be in different time zones. However, the system is heavily compromised by political and geographical considerations, so the rule of the 15 degrees is ignored or bypassed very often. The Earth needs four minutes to rotate one degree, therefore Budapest experiences sunrise, noon and sunset more than one and a half hours earlier than Brest. It is clear that any astronomical instrument, which indicates information like the time of sunrise and sunset, must take into account this difference and cannot simply base its calculations on the current legal or normal time. Additionally, it must ignore further voluntary settings like daylight saving time.
The current local or solar time is indicated by the sun hand, which makes one complete turn every twenty-four hours. The time can be read from the bezel again, but this time by using the Arabic numerals, which show twenty-four hours, although for better clarity they have been omitted at the locations of the roman numerals.
Calendar
The sun hand’s tip serves two purposes: On the calendar ring, it indicates the current month, together with the Arabic numerals on the bezel, the current local or solar time is shown.
The tip of the sun hand on the calendar ring indicates the current month. This ring’s movement is based on the exact duration of the Earth’s orbit around the Sun: 365 days, 5 hours, 48 minutes and 46 seconds. Since it does not subdivide its indication into full days, it is also not necessary to insert any leap days – the Astrolabium’s calendar is always correct.
The day of the week can be read from the window at six o’ clock, and the current sign of the zodiac is indicated by the sun hand’s measure edge on the ecliptic, onto which the zodiac signs are imprinted:
|( |Aries (Ram) March 21–April 19 | |( |Libra (Balance) Sept. 23–Oct. 23 |
|( |Taurus (Bull) April 20–May 20 | |( |Scorpius (Scorpion) Oct. 24–Nov. 21 |
|( |Gemini (Twins) May 21– June 21 | |( |Sagittarius (Archer) Nov. 22–Dec. 21 |
|( |Cancer (Crab) June 22–July 22 | |( |Capricornus (Goat) Dec. 22–Jan. 19 |
|( |Leo (Lion) July 23–Aug. 22 | |( |Aquarius (Water Bearer) Jan. 20–Feb. 18 |
|( |Virgo (Virgin) Aug. 23–Sept. 22 | |( |Pisces (Fish) Feb. 19–March 20 |
Important Astronomical Indications on the Dial
The small circle above the centre of the dial is the zenith, the point of the sky directly above the observer’s head. The location of the zenith depends on the latitudinal position the dial was made for: On the North Pole it would be directly in the dial’s centre, on the equator it would be positioned on the top of the equatorial circle.
The horizon line symbolises the zone where the Earth bars the observer’s view of the sky – only celestial objects above that line are visible. Its radius also depends on the latitudinal position. Under the horizon is the twilight zone, shown as a grey area.
Since the sunlight is scattered in the upper regions of Earth’s atmosphere and by atmospheric dust, there is still some light in the sky, even after the Sun disappears under the horizon. Then it is only possible to see some of the brighter stars. This time is the dusk, and is astronomically defined as being the time between sunset and full night (or complete darkness), which occurs, as the sun is 18 degrees below the horizon. The same is also valid in the morning, when the dawn begins with the sun reaching a position 18 degrees below the horizon, and ends with the sun rising above the latter.
What makes the Astrolabium’s dial look so complicated, is the pattern of lines, which indicate azimuth and elevation lines and help to determine the exact position of a celestial body in the sky. The horizon around us is divided into 360 degrees, which makes it possible to find a star or a planet in the sky just by means of two details: its azimuth, that means its angle from the South direction, and its elevation above the horizon. The Astrolabium’s dial has several guidelines, showing azimuths and elevation angles of 30 and 60 degrees.
Reading the Positions of Sun and Moon
We have to remember, that the ecliptic is the plane in which – more or less exactly – all bodies of our solar system are situated. Therefore, it is only logical that Sun and Moon can be found somewhere on the ecliptic. Intersecting the measure edges of the sun or the moon hands with the outer rim of the ecliptical ring, indicates their exact positions.
In this example the Sun has disappeared about one and a half hours ago, and reached a point about 18 degrees beneath the horizon. The Moon is still visible in the western sky, but will also set in some hours.
Two circular lines on the dial depict the Tropic of Cancer and the Tropic of Capricorn. Due to the 23 degrees-angle of the Earth’s rotation axis towards the ecliptic (see illustration on page XX [10]), the Sun seems to follow a curved path over the year. At the summer or winter solstices it reaches the highest, respectively the lowest point on that curve.
The Sun’s curve over the year
When the Sun (depicted by the intersection of the sun hand’s measure edge with the ecliptic circle’s outer rim) touches the Tropic of Cancer on June 21st, it has reached its highest position in the sky, and the days will become shorter from then on. On December 22nd, the Sun meets the Tropic of Capricorn, symbolizing its lowest position and therefore the shortest day of the year. On March 21st and September 23rd, the Sun crosses the third line depicted on the dial, the equator. During these equinoxes, day and night are equally long.
Sunrise and Sunset, Moonrise and Moonset
The same method is presenting us the exact display of sunrise and sunset, as well as moonrise and moonset: The rise of the Sun or the Moon means that they appear above the horizon. As soon as the intersection point of the sun hand’s measure edge with the ecliptic’s outer rim meets the line of the horizon on the dial, the sunrise occurs. Correspondingly it works with sunset, as well as the rising and the setting of the Moon. Just look at the intersection of the appropriate hand’s measure edge with the ecliptic; when this point meets the horizon line, the awaited event occurs.
As soon as the intersection of the sun hand’s measure edge with the outer rim of the ecliptic reaches the horizon line, the Sun is rising or setting. The picture shows the latter being the case. Afterwards, the Sun will still be in the dusk phase, until total darkness falls.
Dawn and Dusk
As long as the point symbolizing the Sun’s position is somewhere in the grey twilight zone on the dial, there is some light in the sky, although the Sun is not above the horizon. It is either early in the morning (dawn) – then the sun hand/ecliptic intersection is in the left part of the twilight zone – or late in the evening (dusk) – the intersection point is in the right part. As soon as the intersection point leaves the dusk zone, it becomes completely dark.
Depicting the Apparent (Temporal) Time
As has been explained above (page XX [7]), days and nights once had been subdivided into twelve hours each, without regard of the fact that during winter, nights were far longer than during summer. This apparent or temporal time was abandoned only after accurate mechanical clocks became commonly available. The Astrolabium still shows those temporal hours for the nighttime. Doing the same for daytime as well, would have cluttered the dial and therefore reduced its legibility. In the night half of the dial, twelve roman numerals depict the apparent time. Again, the sun hand/ecliptic intersection shows the current hour, but also the differing duration of an apparent hour in summer and winter. As a result of the wish to keep the dial more legible and clear, the limited series platinum Astrolabium does not show the temporal hours.
After sunset, the point of intersection of the sun hand with the ecliptic’s outer rim, together with the roman numerals shows the current apparent (or temporal) time. Here it is about 2.15 o’clock of the nighttime – in summer, when the days are longer it would barely be one o’clock, because the sunset is much later.
Observing the Fixed Stars
Due to the Earth’s course around the Sun, the fixed stars and stellar constellations visible in the sky greatly differ with the seasons on Earth. During winter, one can see other constellations than during summer. All these factors are taken into account by the complex mechanisms of the Astrolabium, so that at any time, you can determine which important stars are currently in the observer’s hemisphere. Many of the brighter fixed stars are printed on the transparent rete of the Astrolabium. As soon as they appear above the horizon line, they are visible in the sky – if it is night, of course. These stars are the main stars (stars of the first magnitude) of important stellar constellations. Due to the limited space on the Astrolabium’s dial it was not possible to depict the complete constellations. Therefore, they are listed in the following table:
|Stars on the Dial |Constellation |Stars on the Dial |Constellation |
|Aldebaran |Taurus (Bull) |Mira |Cetus (Whale) |
|Antares |Scorpius (Scorpion) |Pollux |Gemini (Twins) |
|Arkturus |Bootes (Herdsman) |Procyon |Canis Minor (Smaller Dog) |
|Atair |Aquila (Eagle) |Regulus |Leo (Lion) |
|Beteigeuze |Orion (Hunter) |Rigel |Orion (Hunter) |
|Capella |Auriga (Charioteer) |Sirius |Canis Major (Greater Dog) |
|Deneb |Cygnus (Swan) |Spica |Virgo (Virgin) |
|Fomalhaut |Piscis Austrinus (Southern Fish) |Vega |Lyra (Lyre) |
The highlighted area on the dial is the celestial half-sphere currently visible from the observer’s position. The stars, which are printed on the rete disc, are the main stars of important stellar constellations. They rotate slowly from east to west, so together with the four directions and their distance from the horizon (= red outline), they can be spotted in the dark sky.
The sun hand shows whether the stars are currently observable or not. Smaller stars can be seen only after dusk or before dawn, when it is completely dark. The Astrolabium dial not only informs us about the stars’ visibility, but also about their current position in the sky, so they can be found more easily.
The uppermost position of the dial at twelve o’clock is south, down at six o’clock is north, three o’clock is west, and nine o’clock is east.
Finding Directions
Directions can be found by sighting the Sun (if it is visible) over the sun hand, or by doing the same with the Moon and the moon hand. The four points of the compass are indicated by the roman numerals XII (South), III (West), VI (North) and IX (East) on the bezel.
Moon Phases
The positions of the sun and the moon hands relative to one another indicate the current phase of the Moon. It is essential to remember the path of the Moon around the Earth in relation to the Sun as explained above (page XX [12]). Then it is easy to understand the moon phase display of the Astrolabium at a glance. The axis of the hands can be understood as the location of the Earth. If the moon and sun symbols on the ends of the corresponding hands cover each other on the same side, it means that – regarded from the Earth – both celestial bodies are on the same side. The result is new moon, since the illuminated side of the Moon is facing away from the Earth.
Earth and Moon as seen from Mariner 10
If the sun and moon symbols are opposing each other with the Earth (axis of the hands) in the centre, it is full moon. The Moon’s illuminated side is fully visible from the Earth. The periods between these two events show the Moon either waxing or waning.
Eclipses
The last hand, which has not been mentioned before, is the so-called dragon hand. However, it is shaped more like a snake. It turns slightly faster than the rete, and symbolizes the nodes, where the lunar orbit intersects the ecliptic (see above, page XX [14]). Only when the new moon or full moon occurs on such a node, an eclipse takes place. This can be seen on the Astrolabium, when either the tail or the head (it doesn’t matter which) of the dragon hand is in coverage with the other two hands. At new moon, there is a solar eclipse somewhere on the world, and at full moon a lunar eclipse occurs.
However, keep in mind, that if the dragon hand does show an eclipse occurring, this does not necessarily mean you can observe it. As it has previously been pointed out, a lunar eclipse is visible from the Earth’s night side only, and a solar eclipse is casting a very small shadow on the Earth’s surface. Therefore, it is observable from that narrow shadow zone exclusively – if it is a total eclipse at all, since partial or ring shaped eclipses are far more numerous.
Setting the Astrolabium
Although the mechanism of the Ulysse Nardin Astrolabium is complex, it is very easy to adjust it to the correct time whenever this might be necessary. The perpetual calendar can be corrected forward or backward anytime and without any restriction. All indications can be set by means of the crown only, which means, that no additional correction device, such as pushers, is needed.
The Astrolabium’s crown has three positions; each of them serves a specific purpose:
Position 1: The watch movement can be wound manually.
Position 2: This position serves to set the sun hand, which moves together with the moon hand, the dragon hand and the rete. The hour and minute hands of the normal/legal time do not move when the crown is in this position.
Position 3: The hour and minute hands can be set to the proper time – all other indications automatically are properly adjusted.
How to Set the Astrolabium When it was Stopped for a Time
1. Manually wind the watch a little, with the crown in position 1.
2. Pull out the crown completely (in position 3), and set the hour and minute hands to the current (legal) time. Push the crown back completely into position 1.
3. Then pull the crown out into position 2. Assume that the watch has not been worn since the end of April 2000 and has stopped running. Today is May 21st, 2000. If you take a calendar, which also shows the moon phases, you learn that the last full moon was on May 18th. Therefore, turn the sun hand, until it points to a place somewhere in the middle of the “MAY” field printed on the calendar rim. Continue turning until the sun and moon symbols are positioned directly opposite of each other, which depicts the full moon. If you have turned too far, you only need to turn the hands backward, this is no problem for the watch’s mechanism. Then count each further complete revolution of the sun hand, which equals one day. Turn the sun hand three times to reach the desired date, May 21st. Then set the sun hand to the proper local or solar time, according to the longitudinal position of your current location.
If the watch has not been running for a long period, for some years even, you can use solar or lunar eclipses as reference dates.
How to Adjust the Astrolabium to a New Location
If you change your location along the same degree of latitude, you can adjust the Astrolabium in order to indicate the astronomical events correctly. Of course, any minor changes in your latitudinal (North–South) location do not have grave consequences, but a journey of several thousand miles to the North or the South would make a change of the dial necessary, since this has to be calibrated to your latitudinal location by Ulysse Nardin.
Travelling within the east–west direction of your location only changes the solar time, which means the time when the Sun rises or is in the zenith. In order to have the Astrolabium display its astronomical indications correctly, it is necessary to synchronize the sun hand with the factual course of the Sun in the sky. When the Sun has reached its highest point, the Astrolabium’s sun hand must show twelve o’clock on the 24-hours-bezel. There are two ways to achieve this: The most simple way would be to find a sundial and set the Astrolabium according to the time indicated by the sundial’s shadow pointer. The more complicated, but also better and more scientific way would be to use the current Greenwich Mean Time (GMT) as reference time. If you know your current time zone, for example –5 hours for the time on the United States’ East Coast, you can easily calculate the correct Greenwich time. Just keep in mind, that GMT does not have any daylight saving time, so you might have to deduct or add an hour. In the appendix a GMT chart is printed, which can be of assistance.
After having calculated the current Greenwich time you need the geographic co-ordinates of your current location; a good atlas or a modern GPS receiver can deliver this information. Only the values of the degrees to the West or East are needed. An example: The city of Chicago is located at 87.5 degrees west from Greenwich. As we know, the Earth needs four minutes for every degree to rotate; therefore, the time difference between Greenwich and Chicago is five hours and fifty minutes. When it is noon in Greenwich (without regard to daylight saving time), the sun hand of the Astrolabium in Chicago has to be adjusted so that it is directed to a point shortly after the Arabic 6 (respectively the roman IX) on the bezel.
The Planetarium
For most of the time in the history of human civilisation, the science of astronomy was more or less identical with that of astrology. From the beginning, the observation of celestial bodies served religious purposes, and the most prominent of those bodies, especially the planets, were identified with different deities. All gods were attributed individual characteristics, which again were projected onto their planets. Therefore, it is understandable that their positions relative to the Earth were considered decisive for the different divine influences. The knowledge about the planets’ exact position became crucial for astronomers, and soon automatons were developed to display that information. After 16 years of building time, in 1364, the Italian mathematician and astronomer Giovanni Dondi finished his Astrarium, or Planetarium. This medieval masterpiece of clockmaking not only displayed hours and minutes (the latter for the first time since mechanical clocks were invented), but also a religious perpetual calendar, and the position of the known planets. In later centuries, the planetaria, which since the 18th century were also called orreries, became extremely popular. These mechanisms mainly served the purpose to facilitate the necessary astrological calculations, but also to educate the people about the planetary system as God’s creation as well as Earth’s place in it.
Orrery, made by the English astronomer James Ferguson, as depicted in the first edition of the Encyclopædia Britannica (1768)
The introduction of the heliocentric system by Copernicus caused several problems. Not only did it remove the Earth from the centre of the known universe, degrading it to but one of several planets orbiting around the Sun, and thus challenged the whole system of the world as supported by the Church. Yet it also overthrew all the conceptions of the planets’ movements around the Earth and their astrological importance. The later astrolabes, built according to the new system made any astrological calculations based on the planets’ angles toward the Earth, very difficult, if not impossible.
Jost Bürgi (1552–1632), Swiss mathematician
However, one man solved the discrepancy between scientific knowledge and astrological needs, by simply combining both systems into one automaton or clock: Jost Bürgi (1552–1632), a Swiss mathematician, who was also a gifted watchmaker, physician and astronomer. He invented the logarithmic system, he was one of the very first clockmakers to use a pendulum to adjust clockworks, and he also was the assistant to Johannes Kepler. In 1605, he built a clock with a planetarium dial, now held in the collection of the Museum of History of Arts in Vienna, Austria.
This astronomical clock, built by Jost Bürgi in 1605, is now held by the Museum of History of Art in Vienna. Its unique display of the solar system on the upper dial inspired Ludwig Oechslin when he drafted his Planetarium. The clock’s lower dial features Sun, Moon and a dragon hand for the eclipses, strongly resembling the display on the Astrolabium.
On that dial, Bürgi combined both views of the world by means of taking a fixed axis between the Sun and the Earth as the reference for all the planets’ movements. This resulted in the brilliant compromise of still allowing correct astronomical observations of the planets’ movements relative to the Earth, while offering the radical new view of the world with the Sun in the centre of the solar system.
The upper dial of Bürgi’s magnificent clock shows the typical continental style of planetaria, where the planets are depicted by hands. The more figurative depiction by small spheres was developed on the British Isles. Note the straigth gridlines, which originally were ‘broken’, like those on the Ulysse Nardin Planetarium. A later restoration of the clock is responsible for the wrong grid.
When Ludwig Oechslin saw this clock, he was immediately fascinated by it and consequently, he suggested to Ulysse Nardin to build a similar watch. So the Planetarium is displaying the planetary system in the same way as the Bürgi clock. If any of Ludwig Oechslin’s creations can be understood as a homage to anything or anyone, it is the Planetarium, dedicated to the mathematician, physician, astronomer and watchmaker Jost Bürgi, whom Oechslin admires as one of the most important scientists of his time.
Interpreting the Planetarium
Compared to the highly complex-looking Astrolabium, the Planetarium even seems to be simple; a wrong perception, of course. However, it is a fact that much of the Planetarium’s complexity hides behind the dial.
Reading the Normal Time
The hour and minute hands show the current time on the bezel, which is engraved with the Roman numerals from I to XII. Both hands are covered with luminous mass, to make them legible in the dark (except the limited series platinum Planetarium).
Calendar and Zodiac
Between dial and bezel, a ring is rotating clockwise once a year, showing both the current month and the appropriate sign of the zodiac (see the table above, page XX [32]). A line, leading from the sun to the engraved number XII, facilitates the exact reading of this information. The calendar is again based on the exact duration of the Earth’s revolution around the Sun; 365 days, 5 hours, 48 minutes and 46 seconds. Since it does not subdivide its indication into full days, the insertion of any leap days every four years is not necessary – the Planetarium’s calendar is always correct.
While the hour and minute hands, together with the Roman numerals engraved into the bezel, show the legal time, the ecliptic serves as calendar and zodiac indicator.
The small markers on the ring’s rim are there to help the reading within a month, together with the reference line between the Sun and the Roman figure XII on the bezel; a small polished index shows the beginning of each month.
The progress of the month’s weeks can be followed by means of the reference line between the Earth and twelve o’clock.
Small lines then symbolize the weeks within the month. With the exception of February, all months last longer than four weeks; some have 30, others 31 days. Therefore, eleven of the twelve months are subdivided into five segments, four of them equally long, corresponding to four weeks. The fifth segment stands for the two, respectively three days, where the months last longer than four weeks. February normally lasts exactly four weeks (28 days). Therefore, it is subdivided into four segments only. Since the calendar ring needs a little bit more than one year for one complete revolution, the indication of the weeks will increasingly lag a little bit behind the ‘civil’ calendar we are using. After four years, this lag sums up to approximately one day, and after the civil calendar introduces a leap day in February, the Planetarium’s calendar ring is again on a par with the civil calendar.
The same is valid for the further differences between the factual solar year and our civil calendar year (see above, page XX [11]). One has to keep in mind that the Planetarium’s calendar ring is following the true solar year, and not the year we have printed on our calendars. It is our civil calendar system which deviates from the astronomical reality, because it is based on the completion of full days. Since the subdivision on the Planetarium’s calendar ring is so small, any difference between its display and our civil calendar as small as a fraction of a day hardly matters.
All planets of our solar system – except Pluto – are shown together in that composition from pictures, sent back from NASA orbiters and probes.
All twelve signs of the zodiac subdivide the Earth’s complete revolution around the Sun into sections of 30 degrees each. To facilitate the calculation of a planet’s position against the zodiac, the Planetarium offers the more exact subdivision into segments of five degrees, which are depicted by the small lines on the zodiac’s side of the calendar ring.
Displaying the Planets
The Planetarium displays the six ‘classic’ planets, those known already in the ancient past, since they can be spotted and observed with the naked eye – including our home planet, the Earth of course. These planets have been part of the astrological system developed over centuries. The outmost three planets of our solar system, Uranus, Neptune and Pluto, are so remote from the Earth, that they could be discovered only after the invention of the telescopes, when astrology had lost much of its former importance: Uranus in 1781, Neptune in 1846, and Pluto in 1930.
Following the example of Bürgi’s clock, the Planetarium displays the Earth in a fixed position, so the planets, symbolized by small golden spheres set into the planet rings, do not show their sidereal orbits around the Sun, as an observer positioned outside the solar system would see them. The Planetarium shows their movements in relation to that fixed axis between the Sun and the Earth.
Point of reference for all observations on the Planetarium is the fixed axis between the Sun and the Earth, so Earth’s rotation is simulated by the movement of the ecliptic with the signs of the zodiac, while the other planets are indicated in accordance to that system: The Earth as well as the inner planets, Venus and Mercury, orbit the Sun faster than the outer planets (Mars, Jupiter and Saturn). Therefore, these move clockwise on the Planetarium’s dial, while in reality they, too, circle around the Sun in counterclockwise direction.
Please recall the analogy of the merry-go-round (above, page XX [9]). If you step on it and observe the world outside, taking the axis between you and the platform’s hub as a fixed point of reference, the movement of other people on the playground appears different from what it would look like if you, too, were standing outside the merry-go-round. Therefore, there is a difference of the planets’ true – or sidereal – rotation times around the Sun, and those observed from the Earth, relative to the axis Earth–Sun:
| |Sidereal rotation time around the Sun|Theoretical rotation time around the |Rotation time on Ulysse Nardin’s |
| | |Sun with a fixed Earth |Planetarium |
|Mercury |87.969 days |115.877 days |115.9065 days |
|Venus |224.701 days |583.939 days |584.1 days |
|Mars |1 year 321.738 days |1 year 414.89 days |1 year 414.8923 days |
|Jupiter |11 years 314.9 days |398.875 days |398.8976 days |
|Saturn |29 years 167.2 days |378.0846 days |378.0948 days |
This table also proves the magnificent mechanical precision of the Planetarium’s mechanics, developed by Ludwig Oechslin.
It should be mentioned, however, that in spite of the high overall accuracy of the Planetarium’s display, it is possible that planets are shown in different locations than they are in reality. The reason lies in the elliptical orbits, which all planets maintain around the Sun. The orbits are all more or less eccentric, but the planet rings on the Planetarium dial had to be perfectly circular. A different system would not have been possible in a small wristwatch. Following Kepler’s law, an object on an elliptical orbit would vary its speed, depending on where on the ellpse it is. On the Planetarium, however, its speed is constant. Consequently, any difference between the reality and the Planetarium display will eventually be evened out over the year.
Determining the Planets’ Positions on the Dial
The Planetarium’s sapphire crystal shows a web of lines with the Earth as their centre. These lines span segments of 30 degrees, which help locating the planets relative to the signs of the zodiac. They are not straight, which is caused by the scaling of the planets’ distances on the dial.
The orbit of the inner four planets (Mercury, Venus, Earth and Mars) are relatively near each other, so it was possible to make their planet rings on the Planetarium in the same distance scale relative to the Sun. However, the outer two planets on the dial, Jupiter and Saturn, had to be treated differently, since their distance to the Sun is so large. Had the distance scale of the inner planets been maintained, the ring of Jupiter would have a radius of 34 centimetres, that of Saturn even of 62 centimetres resulting in a “wristwatch” with a diameter of more than 1.25 meters! This watch surely would not be very convenient to wear!
The distances of the inner six planets from the Sun, depicted in scale (in millions of kilometres).
An unusual perspective: Earth seen across the lunar north pole, photographed by the Clementine orbiter.
Therefore, the scale of Jupiter’s distance had to be reduced to a third and for Saturn to a fifth. The lines of the ‘spider web’ on the crystal reflect this change in scale. For each planetary ring they are drawn to show the area which would be seen if the ecliptic was divided into segments of 30 degrees each. The starting point for the spider web is the fixed Earth, whereas the downscaling of the planetary rings uses the Sun as point of reference. Therefore, the lines’ angles have to be adapted correspondingly on the rings of Jupiter and Saturn, resulting in the unique pattern displayed on the Planetarium’s crystal. Thus the outer planets can be correctly located against the circle of the zodiac in spite of the deviation in scale.
The Moon Phases
A small crescent is circling around the globe of the Earth, once exactly in 29 days, 12 hours, 44 minutes and 2.9 seconds; a synodic month.
To read the actual phase of the moon, just keep in mind that the Moon is rotating around the Earth counter-clockwise. As soon as the crescent is exactly between the disc of the Sun and the Earth, it is new moon – the illuminated side of the Moon does not face towards the Earth and therefore is not visible. After that the Moon is waxing until it reaches the position directly opposite the Sun with the Earth between. It is full moon, since the Moon’s illuminated side is fully visible from the Earth. During the following days the Moon is waning again, until the cycle repeats itself.
Setting the Planetarium
The planetary cycles can be easily set by means of the crown only; no additional buttons or pushers are necessary. It is also possible to move the planets forward or backward, so one could simulate the planetary constellation at a given date.
The Planetarium’s crown has three positions:
Position 1: The watch movement can be wound manually.
Position 2: This position serves to move the calendar and the planetary rings, as well as the Moon. One complete turn of the Moon corresponds to 29.53 days or one month. The hour and minute hands do not move when the crown is in this position.
Position 3: The hour and minute hands can be set to the proper time – all other indications automatically are adjusted accordingly.
If the watch stopped for only a few days, the easiest way to reset it would be with the crown in position 3. Any turn of the crown moves the hour and minute hands as well as all the other indications although the latter’s movements are so slow that it might be hard to recognize them. For one day, the hour hand has to make two complete turns on the dial. However, before anything you should wind the watch a little with the crown in position 1, in order to supply the movement with some ‘energy’.
Sometimes, it happens that the watch is not worn for longer time spans; weeks, months or even years. In that case, it would of course be hard work to set the indications forward for years only by means of moving the hour and minute hands. But there is a much easier way to accomplish this. In position 2, the crown allows to move the astronomical indications (planetary and calendar rings as well as the Moon) 800 times faster than in the normal time setting position (pos. 3). The years change into minutes, so the watch can be reset very quickly. But what is even more important: It makes incredible fun to have the planets at one’s command – letting them orbit at your will can make you feel like Mickey Mouse as the “Sorcerer’s Apprentice”! Just remember your original starting point, to reset the watch correctly after playing with it.
If it is necessary to move the indications forward more than just a few days, it’s best to use the quick correcting function of the crown (pos. 2) to find a good reference point. Here it is possible to advance by the days with the crown in position 3. The starting points can be:
a) Full moon,
b) new moon,
c) the first day of a month, or
d) the first day of a zodiac sign.
There are two ways how these points can be read on the watch: either by means of the appropriate markers on the calendar/zodiac ring, lining up with the thin line stretching from the Earth to the twelve o’clock-position, or by the crescent orbiting around the small globe of the Earth and its position relative to the Sun. Just move forward the indication to whatever reference point is nearer to your actual date. Then pull out the crown into position 3 and make the fine adjustment by moving the hour and minute hands.
If the watch has to be updated after it was stopped for years, move forward its indications until the positions of the planets correspond to the following depiction:
These pictures show the planets, how they were positioned on the Planetarium’s dial on January 1st, 2004, 2006, 2008 and 2010. The depictions are not 100% accurate, but illustrate the constellations well enough for our purpose. Turn the crown, until the constellation is similar to one of those shown. Then you have a known date, from which it is rather easy to continue: While now turning the crown, observe the calendar/zodiac ring. Each complete turn of this ring equals one year. Continue until you reach a full moon, or whatever starting point listed above is nearest to your desired date. Then pull out the crown into position 3 and advance by the hours.
Sometimes the friction clutch system, which protects the delicate gearing system from damage, can shift the ecliptic (calendar/zodiac) slightly forward or backward. Mostly this will be barely noticeable, but if necessary, it can be easily corrected by turning the calendar ring with the crown in position 2.
The Tellurium
Telluria always were important parts of large astronomical clocks, because they concentrated their display on those celestial bodies, which are especially important for the human life: Sun, Earth and Moon. By means of the globes displayed by the automatons, one could easily distinguish the areas where it was night or day, while the Moon’s position allowed to determine its current phase.
After the heliocentric view of the world had finally gained common recognition, the telluria normally showed the Sun in the centre, and Earth together with the Moon orbiting around it. The Tellurium of Ulysse Nardin changes that. Here the Earth is positioned in the dial’s centre, leading the term “Tellurium” back to its original roots. “Tellus” is Latin and the Roman analogy of the Greek Gaia, goddess of Earth. Gaia was the centre of the world, the origin and the final destination of everything living and growing. Ludwig Oechslin’s Tellurium reinstalls Gaia’s position as the centre of our every day life. As the completing piece of the Trilogy of Time it also marks the central point on a journey through the cosmos. After looking at the complex concert of the planets and their movements, the view concentrates on the place where we live.
The Tellurium concentrates on a detail of the Planetarium – the system of Sun and Earth. Both are fixed in their positions and the movement of the ecliptic is shown in relation to the axis connecting them.
In its principle, the Tellurium is a close relative to the Planetarium, its dial being a detailed extract of the latter. Both, Sun and Earth are in fixed positions, while the cosmos, symbolized by the zodiac, rotates around them.
Interpreting the Tellurium
Compared with the other two pieces of the Trilogy, the Astrolabium and the Planetarium, the Tellurium outwardly looks simple. But when studied in detail, it discloses itself as being astonishingly complex. By presenting a rotating Earth as viewed from above the North Pole, it is a perfect world time watch, showing the current time on each place on the Earth.
Reading the Time
The legal time currently valid at the user’s location, is indicated by the hour and minute hands on the bezel, which have the figures 1 to 11 (the 12 is showing the Sun symbol) inlaid in blue lacquer. Contrary to conventional watches, these ‘hands’ are mounted on concentric rings, which turn around the central dial. They are covered with luminous mass, so it is possible to read the time in the dark.
Calendar and Zodiac
Between the central dial plate depicting the Earth and the hour and minute hands’ rings, the calendar/zodiac ring is rotating. A full rotation needs 365 days, 5 hours, 48 minutes and 46 seconds, which corresponds to the Earth’s true rotation period around the Sun. A fine line etched into the sapphire crystal is serving as a reference aid.
The calendar and zodiac ring works the same way than that of the Planetarium, therefore the reader is asked to look at the appropriate chapter for reference (see above, page XX [42]). The only difference to the Planetarium’s calendar is the lack of the five-degrees-markers on the zodiac’s side of the ring. Since the Tellurium does not have any planets to be spotted against the zodiac, these indications are not necessary.
Illumination of the Earth
The primary purpose of the Tellurium is to show Earth’s current illumination by the Sun on its central dial. The Sun itself is depicted by the small symbol at the twelve o’clock position of the bezel.
The globe of the Earth is seen from above the North Pole, but in this type of geometric projection, a larger part south of the equator is also visible. Within one day or 24 hours, the disc completes one revolution. The numbers on the outer rim show the 24 time zones, beginning with the prime meridian at Greenwich, near London. In order to indicate night and day on Earth correctly, the disc always has to be synchronized with the World Time, also called Greenwich Mean Time (GMT). Twelve o’clock GMT means that the Sun has reached its highest point in the sky over Greenwich. A line passing through the depiction of the British Isles is the prime meridian and marks the starting point of the time zones. Another fine line in the sapphire crystal facilitates the reading of the Greenwich time.
The area of the Earth disc above the spring is illuminated by the Su,n which is placed as a symbol at twelve o’clock. While the disc turns counterclockwise, the continents depicted rotate into the sunlight (sunrise) or into the shadowed part of the Earth (sunset). The numbers on the Earth disc’s outer rim stand for the 24 timezones while their starting point, the prime meridian at Greenwich, England, is shown by the golden line on the disc. The upper reference line stretching from the sun symbol allows reading the current Greenwich time.
A gold-plated spring stretches across the Earth, showing the current border between daylight and night. The disc’s rotation reproduces the sunrise in the East and the sunset in the West, when the continents, depicted in enamel, pass under the spring. Since Earth’s rotation axis is slanted some 23 degrees relative to the ecliptic, the lengths of night and day change over the year, resulting in the seasons. The spring also reflects this by changing its tension. When it is summer on the Northern Hemisphere, the spring is bent downward, in the direction of the six o’clock position. Then the North Pole can see the polar summer taking place in the sunlight. At the summer solstice (June 21st) the spring has reached its lowest curve, indicating the longest day. Afterwards the curvature is slowly flattened, and on September 23rd the spring is completely straight and horizontal, with day and night equally long on that equinox. During the following weeks, the spring is bending upward, leaving the North Pole in its dark polar night and indicating the steady shortening of the days, until – on December 22nd – this process too, has reached its climax. Then everything reverses again, with the spring displaying the next equinox on March 21st.
Theoretically it is possible to estimate the times of sunrise and sunset for every place on the Earth. Simply find the desired location on the small world disc, and by using the time zones as a base, calculate how many hours separate this point from reaching the spring. But please keep in mind that the enamel disc is a piece of art more than a geographically correct depiction of the Earth, so all these calculations are very rough estimates – which by no means reduces the fun one has when doing this kind of exercise!
The Moon Phases
As the other two watches of the Trilogy series do, the Tellurium, too, displays the current phase of the Moon, but its depiction is more authentic in appearance than the more or less abstract moon phase displays by means of hands or a small crescent.
As in reality, the Tellurium’s Moon circles the Earth counterclockwise, based on the synodic month (29 days, 12 hours, 44 minutes and 2.9 seconds). To illustrate the Moon’s illumination by the Sun, the gold painted half of the moon disc always faces the “Sun” at twelve o’clock, while the dark half depicts the Moon’s shadowed parts, which appear invisible from the Earth. At new moon the Moon is between the Sun and the Earth, with its illuminated side directed away from Earth – the Moon seems invisible.
When its path guides it around the Earth, the Moon is waxing until it reaches the position directly opposite the Sun. Then its illuminated side is fully visible from the Earth, it is full moon. Afterwards the illuminated crescent becomes smaller and smaller; the Moon is waning, until the cycle is completed with the next new moon.
The Moon is depicted by a small disc rotating counterclockwise around the Earth. The dragon’s head and tail indicate solar or lunar eclipses if they align with a new or full moon, respectively.
The Tellurium’s moonphase display is shaped after the nature: Here the Moon is seen circling around the Earth by the Galileo orbiter.
Solar and Lunar Eclipses
The dragon hand, of which only the head and the tip of the tail are visible, symbolizes the nodes where the lunar orbit intersects the ecliptic (see above, page XX [14]). These nodes’ positions also rotate slowly around the Earth, and only when full moon or new moon occur on or near such a node, the view from Earth on either the Sun or the Moon is partially or fully obstructed. The new moon results in a solar eclipse, where the Moon’s disc blocks the Sun, and the full moon disappears in a lunar eclipse, when it is darkened by Earth’s shadow.
These occurrences are depicted on the Tellurium when either the dragon’s head or its tail meets the moon disc at the twelve o’clock position (solar eclipse), or the six o’clock position (lunar eclipse). It is not necessary for the hand and the moon to be perfectly aligned for an eclipse to happen. The dragon hand only shows that in this case the Moon is on or near the node of its orbit. Even if dragon hand and the moon are a little bit off, the conditions for an eclipse might be fulfilled.
As I pointed out previously, the indication of an eclipse on the Tellurium’s dial does not mean that it is observable from everywhere on Earth. Lunar eclipses can only be seen on the night side of the Earth, and solar eclipses are visible on very small areas of the dayside only (see the visibility map of solar eclipses on page XX [13]).
How to Set the Tellurium
The indications of the Tellurium can be easily set, only the crown and a single pusher on the watch’s left side are needed.
The Tellurium’s crown has three positions:
Position 1: The watch movement can be wound manually.
Position 2: This position serves to move the astronomical indications – ecliptic (calendar/zodiac), moon and dragon hand. The hour and minute hands and the Earth’s disc in the centre do not move when the crown is in this position.
Position 3: The hour and minute hands and the current GMT (by means of the central disc) can be set to the proper time. All other indications are adjusted accordingly. When pressing the pusher while the crown is in this position, the astronomical indications do not move when the time is set.
How to Correct the Setting by Short Time Spans (Daylight Saving Time)
Regardless to the time span during which the Tellurium was stopped, it always can be reset to show the proper time very quickly. If this time span was short, it is the easiest way to reset it with the crown in position 3. Nevertheless, before advancing, always wind the watch a little with the crown in position 1, so that the movement has some ‘energy’ to keep the watch working. In position 3, any turning of the crown moves the hour and minute hands, as well as all the other indications. For one day, the hour hand has to make two complete turns on the dial, and the Earth’s disc at the same time rotates once.
Always set the current World Time or GMT first! This is the time of Greenwich near London, without any daylight saving time set. So first you have to know your current time zone. The GMT chart printed in the appendix can be of assistance. On the United States’ East Coast, for example, you have to add five hours to get the current GMT. During summer, however, you only have to add four hours, since the daylight saving time already has added one hour.
Let us assume you are living in Washington, D.C. and have to reset the Tellurium, which did not run for a day. Your actual time is 10.15 a.m. In Greenwich time this would be 03.15 p.m. (or 15.15). During daylight saving time, 10.15 in Washington would be only 14.15 in Greenwich. In position 3 turn the crown, until the reference line beneath the “Sun” at twelve o’clock aligns with the correct GMT on the 24-hour indicator on the world disc. Now you have set the world disc to show the correct phase of the day. Then press the pusher on the watch’s left side and hold it, while you turn back the hour and minute hands with the crown until they correctly show 10.15 o’clock, the time on your current location.
Basically the same procedure is followed on the days when the daylight saving time is introduced or ended, or if you are travelling into a different time zone, although it generally is dispensable to change the GMT setting of the Earth’s disc if the watch was running all the time. Therefore, you only have to pull out the crown into position 3, press the pusher and hold it, while you set the new time by turning the crown.
Changing the Time, Taking into Account long Time Spans
If it is necessary to change the indications for more than just a few days, it is the best to use the quick correcting function of the crown (pos. 2) to find a good reference point. It is then possible to advance by the days with the crown in position 3. The starting points can be:
a) Full moon,
b) new moon,
c) the first day of a month, or
d) the first day of a zodiac sign.
These points can be read on the watch by means of the appropriate markers on the calendar/zodiac ring, lined up with the thin reference line beneath the sun symbol. Alternatively, the moon disc orbiting around the disc of the Earth and its position relative to the Sun can serve as an adjustment aid. Just move the indication forward to whatever reference point is nearer to your actual date. Then pull out the crown into position 3 and make the fine adjustment by moving the hour and minute hands. Here you may first set the correct Greenwich Time again. Then press the pusher and hold it while setting your current local time so that the other indications do not change accordingly.
If the watch has to be updated after being stopped for over a year, move its indications forward until the positions of the Moon and the dragon hand correspond to the positions relative to the minute indications, as given in the following table:
|Positions of moon and dragon hand on January 1st 2000–2021 |
|(relative to the minute indications) |
|Year |Moon |Dragon |Year |Moon |Dragon |
|2000 |12 |26 |2011 |9 |1 |
|2001 |50 |29 |2012 |47 |5 |
|2002 |28 |32 |2013 |25 |8 |
|2003 |6 |36 |2014 |3 |11 |
|2004 |44 |39 |2015 |41 |14 |
|2005 |22 |42 |2016 |19 |17 |
|2006 |60 |45 |2017 |56 |21 |
|2007 |37 |48 |2018 |34 |24 |
|2008 |15 |52 |2019 |12 |27 |
|2009 |53 |55 |2020 |50 |30 |
|2010 |31 |58 |2021 |28 |34 |
This table shows how the Moon and the dragon hand were positioned on the Tellurium’s dial on January 1st, 2000–2021. From that point turn the crown (in position 2) and observe the calendar/zodiac ring: Each complete turn of this ring equals one year. Continue until you reach a full moon, or whatever starting point listed above is nearest to your desired date. Then pull out the crown into position 3 and advance by the hours, until the correct GMT is reached. Finally, press the pusher and hold it while you set the desired local time.
Sometimes the friction clutch system, which protects the delicate gearing system from damage, can shift the ecliptic (calendar/zodiac) slightly forward or backward. Mostly this will be barely noticeable, but if necessary it can be easily corrected by turning the calendar ring with the crown in position 2.
Appendix: International Time Zones
Acknowledgments
Text and illustrations: Dr. Marcus Hanke, University of Salzburg;
photographs: pages XX [3], XX [5], XX [13], XX [15]: Marcus Hanke, Salzburg;
page XX [41]: Museum of History of Arts, Vienna;
pages XX [12], XX [36], XX [43], XX [45], XX [52]: NASA;
page XX [20]: Türler, Zurich;
all others: Ulysse Nardin, Le Locle.
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related download
Related searches
- how to fix low resolution photos
- convert low resolution to high resolution
- make low resolution picture high resolution
- how to fix low resolution photos walgreens
- alabama map with all cities
- calculator with all buttons
- fixing low resolution photos website
- 1040 instructions booklet for 2018
- hondas with all wheel drive
- low resolution to high resolution converter
- density calculator with all work shown
- design a booklet for free