Tycho Brahe

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Tycho Brahe (born Tyge Ottesen Brahe) (December 14, 1546October 24 1601) was a Danish nobleman known primarily for his work as an astronomer and an astrologer (the two were highly related in his day), as well as an alchemist. He was granted an estate on the island of Hven and the funding to build the Uraniborg, an early research institute, where he built large astronomical instruments and took many careful measurements. As an astronomer, Tycho worked to combine what he saw as the geometrical benefits of the Copernican system with the philosophical benefits of the Ptolemaic system into his own model of the universe, the Tychonian system. His best known assistant was Johannes Kepler, who would later use Tycho's astronomical information to develop his own theories of astronomy.

He is universally referred to as "Tycho" rather than by his surname "Brahe." Apparently his contemporaries did so and the usage has persisted. His name is pronounced /ˈtyˌko ˈbʁɒˌhɛ/, according to transcription in the International Phonetic Alphabet (in English, it is thought that Teeko is a close approximation of its probable pronunciation).

While credited with the most accurate astronomical observations of his time, he was unable to carry the implications of the voluminous data he collected to its logical consequences; it was his assistant, Johannes Kepler, whose superior mathematical faculty would enable the full interpretation of his master's acute observations and allow for the discovery of the laws of planetary motion (it should also be noted that none before Tycho had attempted to make so many redundant observations, and the mathematical tools to take advantage of them had not yet been developed). Nonetheless, his mark in science should not be understated, for he had done what others before him were unable or unwilling to do — to catalogue the planets and stars with enough accuracy so as to determine whether the Ptolemaic or Copernican system was more valid in describing the heavens.

Early years

Tycho Brahe was born Tyge Ottesen Brahe (de Knudstrup), adopting the Latinised form Tycho at around age fifteen (sometimes written Tÿcho). He is often misnamed Tycho de Brahe. He was born at his family's ancestral seat of Knudstrup Castle, Denmark to Otte Brahe and Beate Bille. His twin brother was stillborn (Tycho wrote a Latin ode (Wittendorf 1994, p. 68) to his dead twin which was printed as his first publication in 1572). He also had two sisters, one older (Kirstine Brahe) and one younger (Sophie Brahe). Otte Brahe, Tycho's father, a nobleman, was an important figure in the Danish King's court. Beate Bille, Tycho's mother, also came from an important family which had produced leading churchmen and politicians.

Tycho later wrote that when he was around two, his uncle, Danish nobleman Jørgen Brahe, ... without the knowledge of my parents took me away with him while I was in my earliest youth. Apparently this did not lead to any disputes nor did his parents attempt to get him back. Tycho lived with his childless uncle and aunt, Jørgen Brahe and Inger Oxe, in the Tostrup Castle until he was six years old. Around 1552 his uncle was given the command of Vordingborg Castle to which they moved, and where Tycho began a Latin education until he was 12 years old.

On April 19 1559, Tycho began his studies at the University of Copenhagen. There, following the wishes of his uncle, he studied law but also studied a variety of other subjects and became interested in astronomy. It was, however, the eclipse which occurred on August 21 1560, particularly the fact that it had been predicted, that so impressed him that he began to make his own studies of astronomy helped by some of the professors. He purchased an ephemeris and books such as Sacrobosco's Tractatus de Sphaera, Apianus's Cosmographia seu descriptio totius orbis and Regiomontanus's De triangulis omnimodis.

I've studied all available charts of the planets and stars and none of them match the others. There are just as many measurements and methods as there are astronomers and all of them disagree. What's needed is a long term project with the aim of mapping the heavens conducted from a single location over a period of several years. — Tycho Brahe, 1563 (aged 17).

Tycho realized that progress in the science of astronomy could be achieved not by occasional haphazard observations, but only by systematic and rigorous observation, night after night, and by using instruments of the highest accuracy obtainable. He was able to improve and enlarge the existing instruments, and construct entirely new ones. Tycho's naked eye measurements of planetary parallax were accurate to the arcminute. (These measurements became the possessions of Kepler following Tycho's death.)

While a student, Tycho lost part of his nose in a duel with broadswords with Manderup Parsbjerg, a fellow Danish nobleman. This occurred in the Christmas season of 1566, after a fair amount of drinking, while the just turned 20-year-old Tycho was studying at the University of Rostock in Germany. Attending a dance at a professor's house, he quarrelled with Parsbjerg. A subsequent duel (in the dark) resulted in Tycho losing the bridge of his nose. A consequence of this was that Tycho developed an interest in medicine and alchemy. For the rest of his life, he was said to have worn a replacement made of silver and gold blended into a flesh tone, and used an adhesive balm to keep it attached. In 1901, though, Tycho's tomb was reopened and his remains were examined by medical experts. The nasal opening of the skull was rimmed with green, a sign of exposure to copper, not silver or gold. Some historians have speculated that he wore a number of different prosthetics for different occasions, noting that a copper nose would have been more comfortable and less heavy than one of precious metals.

Death of his father

His foster father, uncle Jørgen Brahe, had already died in 1565 of pneumonia after rescuing Frederick II of Denmark from drowning. In April 1567, Tycho returned home from his travels, where his father wanted him to take up law, but was allowed to make trips to Rostock, then on to Augsburg (where he built a great quadrant), Basel, and Freiburg. He was informed about his father's illness at the end of 1570, so he returned to Knudstrup, where his father died in May 1571. Soon after, his other uncle Steen Bille helped him build an observatory and alchemical laboratory at Herrevad Abbey.

Family life

In 1572, in Knudstrup, Tycho fell in love with Kirsten Jørgensdatter, a commoner whose father, Pastor Jorgen Hansen, was the Lutheran clergyman of Knudstrup's village church. Under Danish law, when a nobleman and a common woman lived together openly as husband and wife, and she wore the keys to the household at her belt like any true wife, their alliance became a binding morganatic marriage after three years. The husband retained his noble status and privileges; the wife remained a commoner. Their children were legitimate in the eyes of the law, but they were commoners like their mother and could not inherit their father's name, coat of arms, or land property. (Skautrup 1941, pp. 24-5)

Kirsten Jørgensdatter gave birth to their daughter, Kirstine (named after Tycho's late sister who died at 13) on October 12, 1573.


On November 11, 1572, Tycho observed (from Herrevad Abbey) a very bright star which unexpectedly appeared in the constellation Cassiopeia, now named SN 1572. Since it had been maintained since antiquity that the world of the fixed stars was eternal and unchangeable (a fundamental axiom of the Aristotelian world view: celestial immutability), other observers held that the phenomenon was something in the Earth's atmosphere. Tycho, however, observed that the parallax of the object did not change from night to night, suggesting that the object was far away. Tycho argued that a nearby object should appear to shift its position with respect to the background. He published a small book, De Stella Nova (1573), thereby coining the term nova for a "new" star (we now know that Tycho's star was a supernova). 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 Stella Nova: "O crassa ingenia. O caecos coeli spectatores" ("Oh thick wits. Oh blind watchers of the sky").

Tycho's discovery was the inspiration for Edgar Allan Poe's poem, Al Aaraaf.


Kepler tried, but was unable, to persuade Tycho to adopt the heliocentric model of the solar system. Tycho believed in a modified geocentric model known as the Tychonian system, for the same reasons that he argued that the supernova of 1572 was not near the Earth. He argued that if the Earth were in motion, then nearby stars should appear to shift their positions with respect to background stars. In fact, this effect of parallax does exist; it could not be observed with the naked eye, or even with the telescopes of the next two hundred years, because even the nearest stars are much more distant than most astronomers of the time believed possible.

Uraniborg, Stjerneborg and Benátky nad Jizerou

File:Uraniborgskiss 90.jpg
Watercolor plan of Uraniborg

King Frederick II of Denmark and Norway, impressed with Tycho's 1572 observations, financed the construction of two observatories for Tycho on the island of Hven in Copenhagen Sound. These were Uraniborg and Stjerneborg. Uraniborg also had a laboratory for his alchemical experiments.

Because Tycho disagreed with Christian IV, the new king of his country, he moved to Prague in 1599. Sponsored by Rudolf II, the Holy Roman Emperor, he built a new observatory (in a castle in Benátky nad Jizerou, 50 km from Prague) and worked there until his death.

In return for their support, Tycho's duties included preparing astrological charts and predictions for his patrons on events such as births, weather forecasting and astrological interpretations of significant astronomical events such as the comet of 1577 and the supernova of 1572.

Tycho and astronomy

Mural quadrant (Tycho Brahe 1598)

Tycho was the preeminent observational astronomer of the pre-telescopic period, and his observations of stellar and planetary positions achieved unparalleled accuracy for their time. For example, Tycho measured Earth's axial tilt as 23 degrees and 31.5 minutes, which he claimed to be more acurate than Copernicus by 3.5 minutes. After his death, his records of the motion of the planet Mars enabled Kepler to discover the laws of planetary motion, which provided powerful support for the Copernican heliocentric theory of the solar system.

Tycho himself was not a Copernican, but proposed a system in which the planets other than Earth orbited the Sun while the Sun orbited the Earth. His system provided a safe position for astronomers who were dissatisfied with older models but were reluctant to accept the Earth's motion. It gained a considerable following after 1616 when Rome decided officially that the heliocentric model was contrary to both philosophy and Scripture, and could be discussed only as a computational convenience that had no connection to fact. His system also offered a major innovation: while both the geocentric model and the heliocentric model as set forth by Copernicus relied on the idea of transparent rotating crystalline spheres to carry the planets in their orbits, Tycho eliminated the spheres entirely.

He was aware that a star observed near the horizon appears with a greater altitude than the real one, due to atmospheric refraction, and he worked out tables for the correction of this source of error.

To perform the huge number of products needed to produce much of his astronomical data, Tycho relied heavily on the then-new technique of prosthaphaeresis, an algorithm for approximating products based on trigonometric identities that predated logarithms.

Tycho and Astrology

Like the fifteenth century astronomer Regiomontanus, Tycho Brahe appears to have accepted astrological prognostications on the principle that the heavenly bodies undoubtedly influenced (yet did not determine) terrestrial events, but expressed skepticism about the multiplicity of interpretative schemes, and increasingly preferred to work on establishing a sound mathematical astronomy. Two early tracts, one entitled Against Astrologers for Astrology, and one on a new method of dividing the sky into astrological houses, were never published and are unfortunately now lost.

Tycho also worked in the area of weather prediction, produced astrological interpretations of the supernova of 1572 and the comet of 1577, and furnished his patrons Frederick II and Rudolph II with nativities and other predictions (thereby strengthening the ties between patron and client by demonstrating value). An astrological worldview was fundamental to Tycho's entire philosophy of nature. His interest in alchemy, particularly the medical alchemy associated with Paracelsus, was almost as long-standing as his study of astrology and astronomy simultaneously, and Uraniborg was constructed as both observatory and laboratory.

In an introductory oration to the course of lectures he gave in Copenhagen in 1574, Tycho defended astrology on the grounds of correspondences between the heavenly bodies, terrestrial substances (metals, stones etc.) and bodily organs. He was later to emphasise the importance of studying alchemy and astrology together with a pair of emblems bearing the mottoes: Despiciendo suspicio ("By looking down I see upward") and Suspiciendo despicio ("By looking up I see downward"). As several scholars have now argued, Tycho's commitment to a relationship between macrocosm and microcosm even played a role in his rejection of Copernicanism and his construction of a third world-system.

Tycho's elk

Tycho often held large social gatherings in his castle, as he was a member of the nobility. He was said to own 1% of the entire wealth of Denmark at one point in the 1580s. Pierre Gassendi wroteTemplate:Fn that Tycho also had a tame elk, and that his mentor the Landgraf Wilhelm of Hesse-Kassel asked about an animal faster than a deer. Tycho replied writing there were 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 just died on a visit to entertain a nobleman at Landskrona. Apparently during dinner the elk had drunk a lot of beer and fell down the stairs, and died.Template:Fn

Tycho's death

Tycho died on October 24 1601, several days after straining his bladder during a banquet. It has been said that to leave the banquet before it concluded, would be the height of bad manners and so he remained. His weakened state allowed an infection to invade his body and lead ultimately to his death. He was succeeded as Imperial Mathematicus by Kepler, two days later.

However, recent investigations have suggested that Tycho did not die from urinary problems but most likely from mercury poisoning: toxic levels of it have been found in his hair and hair-roots. Tycho may have poisoned himself unintentionally by imbibing some mercury-containing medicine.Template:Fn Some have even speculated that Tycho may have been murdered, though there is no solid evidence for this.

Tycho Brahe's body is currently interred in a tomb in the Church of Our Lady of Tyn on Old Town Square near Prague Astronomical Clock in Prague.

Further reading

  • John Robert Christianson: On Tycho's Island: Tycho Brahe, science, and culture in the sixteenth century. Cambridge: Cambridge University Press, 2000 ISBN 0-521-65081-X
  • Victor E. Thoren: The Lord of Uraniborg: a biography of Tycho Brahe. Cambridge: Cambridge University Press, 1990 ISBN 0-521-35158-8
  • Kitty Ferguson: The nobleman and his housedog: Tycho Brahe and Johannes Kepler: the strange partnership that revolutionised science. London : Review, 2002 ISBN 0-747270-22-8 (published in the US as: Tycho & Kepler: the unlikely partnership that forever changed our understanding of the heavens. New York: Walker, 2002 ISBN 0-8027-1390-4)
  • Joshua Gilder and Anne-Lee Gilder Heavenly intrigue. New York: Doubleday, 2004 ISBN 0-385-50844-1


External links

Named after Tycho

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