Science and life on Uraniborg
In April 1567, Tycho returned home from his travels, with a firm intention of becoming an astrologer. Although he had been expected to go into politics and the law, like most of his kinsmen, and although Denmark was still at war with Sweden, his family supported his decision to dedicate himself to the sciences. His father wanted him to take up law, but Tycho was allowed to travel to Rostock and then to Augsburg, where he built a great quadrant, then Basel, and Freiburg. In 1568, he was appointed a canon at Roskilde Cathedral in Denmark, a largely honorary position that allowed him to focus on his studies.
At the end of 1570, he was informed of his father's ill health, so he returned to Knutstorp Castle, where his father died on 9 May 1571. The war was over, and the Danish lords soon returned to prosperity. Soon, another uncle, Steen Bille, helped him build an observatory and alchemical laboratory at Herrevad Abbey, where Tycho was assisted by his keenest disciple, his younger sister Sophie Brahe. Tycho was acknowledged by King Frederick II, who proposed to him that an observatory be built to better study the night sky. After accepting this proposal, the location for the Uraniborg’s construction was set on an island called Hven, now Ven in the Sound not too far from Copenhagen, the earliest large observatory in Christian Europe.
Tycho Brahe was highly appreciated by King Frederick II, and he was accepted and supported by people of high social status. He was supported by the church. The support Tycho Brahe received from the king allowed him to continue his research and make significant contributions to the field of astronomy.
In the late 16th century, Tycho Brahe built an observatory called Uraniborg. It was built on the island of Hven located between the provinces of Zealand (Sjælland) and Scania (Skåne). The island was then an administrative part of Zealand. Later, after the Peace of Roskilde in 1658, Scania was conquered by the Swedes. In 1660, Hven became part of Sweden. In Tycho's time, it was all Denmark. He lived on Hven for approximately 21 years. He began to build Uraniborg in 1576 and moved there soon after. As Uraniborg was a significant and advanced observatory, it took years to complete.
Uraniborg was a place where Tycho Brahe could research and analyze his previous findings, as well as explore new discoveries. Tycho Brahe was an astronomer of the pre-telescope era. Using just his naked eye, he observed the planets, Moon, stars, and space and recorded everything he saw while completing a multitude of calculations daily. The location of Uraniborg was strategically chosen, with seclusion and support being the primary reasons for building on the island of Hven. Seclusion was essential for accurate observation, and gave Tycho Brahe a better way to focus on his work without worrying about interruptions from other people. Seclusion was also important for observation, as there was nothing interfering with time, light, or motion observations.
Tycho Brahe was a perfectionist, and by being secluded he had complete control over his research and was not limited by anyone else's restrictions, enabling him to develop innovative research. He could focus all of his energy on his work, without receiving any backlash or questioning from anyone. The seclusion gave him the freedom to pursue his research without limitations and paved the way for groundbreaking discoveries in the field of astronomy. Uraniborg was one of the most advanced observatories of its time, equipped with several astronomical instruments, including quadrant instruments, sextants, and astronomical clocks.
Tycho Brahe's observations and calculations at Uraniborg allowed him to develop more accurate Solar System models. He compiled the most extensive and accurate catalog of stellar positions up to that time. Tycho Brahe's observations and calculations at Uraniborg allowed him to lay the groundwork for astronomers in the future.
Despite the success Tycho Brahe had on Hven, he eventually left the island after a disagreement with the new king of Denmark, Christian IV. In 1597, Tycho Brahe moved to Prague, where he continued his work and was eventually appointed by Emperor Rudolf II in 1601 as imperial mathematician. However, Uraniborg remained a significant landmark in the history of astronomy.
Towards the end of 1571, Tycho fell in love with Kirsten, daughter of Jørgen Hansen, the Lutheran minister in Knudstrup. As she was a commoner, Tycho never formally married her, since if he did he would lose his noble privileges. However, Danish law permitted morganatic marriage, which meant that a nobleman and a common woman could live together openly as husband and wife for three years, and their alliance then became a legally binding marriage. However, each would maintain their social status, and any children they had together would be considered commoners, with no rights to titles, landholdings, coat of arms, or even their father's noble name.
While King Frederick respected Tycho's choice of wife, himself having been unable to marry the woman he loved, many of Tycho's family members disagreed, and many churchmen continued to hold the lack of a divinely sanctioned marriage against him. Kirsten Jørgensdatter gave birth to their first daughter, Kirstine, named after Tycho's late sister, on 12 October 1573. Kirstine died from the plague in 1576. Tycho wrote a heartfelt elegy for her tombstone. In 1574, they moved to Copenhagen where their daughter Magdalene was born. Later the family followed him into exile. Kirsten and Tycho lived together for almost thirty years until Tycho's death. Together, they had eight children, six of whom lived to adulthood.
On 11 November 1572, Tycho observed, from Herrevad Abbey, a very bright star, now numbered SN 1572, which had unexpectedly appeared in the constellation Cassiopeia. Because it had been maintained since antiquity that the world beyond the Moon's orbit was eternally unchangeable, with celestial immutability being a fundamental axiom of the Aristotelian world-view, other observers held that the phenomenon was something in the terrestrial sphere below the Moon. However, Tycho observed that the object showed no daily parallax against the background of the fixed stars. This implied that it was at least farther away than the Moon and those planets that do show such parallax. He found that the object did not change its position relative to the fixed stars over several months, as all planets did in their periodic orbital motions, even the outer planets, for which no daily parallax was detectable.
This suggested that it was not even a planet, but a fixed star in the stellar sphere beyond all the planets. In 1573, he published a small book De nova stella, coining the term nova for a "new" star. This star was a supernova and is 7,500 light-years from Earth. This discovery was decisive for his choice of astronomy as a profession. Tycho was strongly critical of those who dismissed the implications of the astronomical appearance, writing in the preface to De nova stella: "O crassa ingenia. O caecos coeli spectatores" ("O thick wits. O blind watchers of the sky"). The publication of his discovery made him a well-known name among scientists in Europe.
Tycho continued with his detailed observations, often assisted by his first assistant and student, his younger sister Sophie. In 1574, Tycho published the observations made in 1572 from his first observatory at Herrevad Abbey. He then started lecturing on astronomy, but gave it up and left Denmark in spring 1575 to tour abroad. He first visited William IV, Landgrave of Hesse-Kassel's observatory at Kassel, then went on to Frankfurt, Basel, and Venice, where he acted as an agent for the Danish king, contacting artisans and craftsmen whom the king wanted to work on his new palace at Elsinore. Upon his return, the King wished to repay Tycho's service by offering him a position worthy of his family. He offered him a choice of lordships of militarily and economically important estates, such as the castles of Hammershus or Helsingborg.
Tycho was reluctant to take up a position as a lord of the realm, preferring to focus on his science. He wrote to his friend Johannes Pratensis, "I did not want to take possession of any of the castles our benevolent king so graciously offered me. I am displeased with society here, customary forms and the whole rubbish". Tycho secretly began to plan to move to Basel, wishing to participate in the burgeoning academic and scientific life there. The King heard of Tycho's plans, and desiring to keep the distinguished scientist, in 1576 he offered Tycho the island of Hven in Øresund and funding to set up an observatory.
Until then, Hven had been property directly under the Crown. The 50 families on the island considered themselves to be freeholding farmers, but with Tycho's appointment as Feudal Lord of Hven, this changed. Tycho took control of agricultural planning, requiring the peasants to cultivate twice as much as they had done before, and he exacted corvée labor from the peasants for the construction of his new castle. The peasants complained about Tycho's excessive taxation and took him to court. The court established Tycho's right to levy taxes and labor. The result was a contract detailing the mutual obligations of lord and peasants on the island.
Tycho envisioned his castle Uraniborg as a temple dedicated to the muses of arts and sciences, rather than as a military fortress. It was named after Urania, the muse of astronomy. Construction began in 1576, with a laboratory for his alchemical experiments in the cellar. Uraniborg was inspired by the Venetian architect Andrea Palladio. It was one of the first buildings in northern Europe to show influence from Italian renaissance architecture.
When he realized that the towers of Uraniborg were not adequate as observatories, because of the instruments' exposure to the elements and the movement of the building, he constructed an underground observatory close to Uraniborg called Stjerneborg (Star Castle) in 1584. This consisted of several hemispherical crypts which contained the great equatorial armillary, large azimuth quadrant, zodiacal armillary, largest azimuth quadrant of steel and the trigonal sextant.
The basement of Uraniborg included an alchemical laboratory, with 16 furnaces for conducting distillations and other chemical experiments. Unusually for the time, Tycho established Uraniborg as a research centre, where almost 100 students and artisans worked from 1576 to 1597. Uraniborg contained a printing press and a paper mill, both among the first in Scandinavia, enabling Tycho to publish his own manuscripts, on locally made paper with his own watermark. He created a system of ponds and canals to run the wheels of the paper mill. Another resident of Uraniborg was a man with dwarfism named Jeppe, whom Tycho believed had the ability to predict the future, and he allegedly was able to correctly predict the chances of recovery or death of ill people in Hven.
Over the years he worked on Uraniborg, Tycho was assisted by a number of students and protegés, many of whom went on to their own careers in astronomy. Among them were Christian Sørensen Longomontanus, later one of the main proponents of the Tychonic model and Tycho's replacement as royal Danish astronomer, Peder Flemløse, Elias Olsen Morsing, and Cort Aslakssøn. Tycho's instrument-maker Hans Crol formed part of the scientific community on the island.
Tycho observed the Great Comet of 1577, which was visible in the Northern sky from November 1577 to January 1578. Within Lutheranism, it was commonly believed that celestial objects like comets were powerful portents, announcing the coming apocalypse. Several Danish amateur astronomers observed the object and published prophesies of impending doom. Tycho was able to determine that the comet's distance to Earth was much greater than the distance of the Moon, so that the comet could not have originated in the "earthly sphere", confirming his prior anti-Aristotelian conclusions about the fixed nature of the sky beyond the Moon.
Tycho realized that the comet's tail was always pointing away from the Sun. He calculated its diameter, mass, and the length of its tail, and speculated about the material it was made of. Through nightly observations of the comet, Tycho Brahe estimated its closest approach to Earth at about 230 times the Earth's radius. He also analyzed its motion, suggesting an orbit located between Mercury and Venus.
At this point, he had not yet broken with Copernican heliocentrism, and observing the comet inspired him to try to develop an alternative Copernican model, in which the Earth was immobile. Tycho Brahe's comet observations challenged the prevailing theory of solid celestial spheres. With the comet likely traveling between Mercury and Venus, the notion of these rigid spheres became untenable. It suggested a vast emptiness where objects like the comet, potentially quite large, could move freely and exhibit properties unlike those previously understood. The second half of his manuscript about the comet dealt with the astrological and apocalyptic aspects of the comet. Tycho rejected the prophesies of his competitors. Instead, he made his own predictions of dire political events in the near future. Among his predictions was bloodshed in Moscow, and the imminent fall of Ivan the Terrible by 1583.
The support that Tycho received from the Crown was substantial, amounting to 1% of the annual total revenue at one point in the 1580s. Tycho often held large social gatherings in his castle. Pierre Gassendi wrote that Tycho had a tame elk and that his mentor the Landgrave Wilhelm of Hesse-Kassel asked whether there was an animal faster than a deer. Tycho replied that there was none, but he could send his tame elk. When Wilhelm replied he would accept one in exchange for a horse, Tycho replied with the sad news that the elk had just died on a visit to entertain a nobleman at Landskrona. Apparently, during dinner, the elk had drunk a lot of beer, fallen down the stairs, and died.
Among the many noble visitors to Hven was James VI of Scotland, who married the Danish princess Anne. He gave gold coins to the ferryman and to the builders and workers at Tycho's paper mill. After his visit to Hven in 1590, James wrote a poem comparing Tycho with Apollon and Phaethon.
As part of Tycho's duties to the Crown, in exchange for his estate, he fulfilled the functions of a royal astrologer. At the beginning of each year, he had to present an Almanac to the court, predicting the influence of the stars on the political and economic prospects of the year. At the birth of each prince, he prepared their horoscopes, predicting their fates. He also worked as a cartographer with his former tutor Anders Sørensen Vedel on mapping out all of the Danish realm. An ally of the king and friendly with Queen Sophie, both his mother Beate Bille and adoptive mother Inger Oxe had been her court maids, he secured a promise from the King that ownership of Hven and Uraniborg would pass to his heirs.
In 1588, Tycho's royal benefactor died, and a volume of Tycho's great two-volume work Astronomiae Instauratae Progymnasmata (Introduction to the New Astronomy) was published. The first volume, devoted to the new star of 1572, was not ready, because the reduction of the observations of 1572–73 involved much research to correct the stars' positions for refraction, precession, the motion of the Sun etc., and was not completed in Tycho's lifetime. It was published in Prague in 1602–1603.
The second volume, titled De Mundi Aetherei Recentioribus Phaenomenis Liber Secundus (Second Book About Recent Phenomena in the Celestial World) and devoted to the comet of 1577, was printed at Uraniborg and some copies were issued in 1588. Besides the comet observations, it included an account of Tycho's system of the world. The third volume was intended to treat the comets of 1580 and following years in a similar manner. It was never published, or written, though a great deal of material about the comet of 1585 was put together and published in 1845 with the observations of this comet.
While at Uraniborg, Tycho maintained correspondence with scientists and astronomers across Europe. He inquired about other astronomers' observations and shared his own technological advances to help them achieve more accurate observations. Thus, his correspondence was crucial to his research. Often, correspondence was not just private communication between scholars, but also a way to disseminate results and arguments and to build progress and scientific consensus. Through correspondence, Tycho was involved in several personal disputes with critics of his theories. Prominent among them were John Craig, a Scottish physician who was a strong believer in the authority of the Aristotelian worldview, and Nicolaus Reimers Baer, known as Ursus, an astronomer at the Imperial court in Prague, whom Tycho accused of having plagiarized his cosmological model.
Craig refused to accept Tycho's conclusion, that the comet of 1577 had to be located within the aetherial sphere, rather than within the atmosphere of Earth. Craig tried to contradict Tycho by using his own observations of the comet, and by questioning his methodology. Tycho published an apologia (a defense) of his conclusions, in which he provided additional arguments, as well as condemning Craig's ideas in strong language for being incompetent. Another dispute concerned the mathematician Paul Wittich, who, after staying on Hven in 1580, taught Count Wilhelm of Kassel and his astronomer Christoph Rothmann to build copies of Tycho's instruments without permission from Tycho. Craig, who had studied with Wittich, accused Tycho of minimizing Wittich's role in developing some of the trigonometric methods used by Tycho. In his dealings with these disputes, Tycho made sure to leverage his support in the scientific community, by publishing and disseminating his own answers and arguments.
