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Tycho Brahe, born Tyge Ottesen Brahe (de Knudstrup) (14 December 1546 – 24 October 1601), was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations. Coming from Scania, then part of Denmark, now part of modern-day Sweden, Tycho was well known in his lifetime as an astronomer and alchemist.

His Danish name "Tyge Ottesen Brahe" is pronounced in Modern Standard Danish as . He adopted the Latinized name "Tycho Brahe" (usually or in English) from Tycho (sometimes written Tÿcho) at around age fifteen, and he is now generally referred to as "Tycho" rather than by his surname "Brahe", as was common in Scandinavia in the 17th century. (The incorrect form of his name, Tycho de Brahe, appeared only much later.)

Tycho Brahe was granted an estate on the island of Hvenmarker and the funding to build the Uraniborgmarker, an early research institute, where he built large astronomical instruments and took many careful measurements. After disagreements with the new king in 1597, he was invited by the Bohemian king and Holy Roman emperor Rudolph II to Prague, where he became the official imperial astronomer. He built the new observatory at Benátky nad Jizeroumarker. Here, from 1600 until his death in 1601, he was assisted by Johannes Kepler. Kepler would later use Tycho's astronomical information to develop his own theories of astronomy.

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 Tychonic system.

Tycho is credited with the most accurate astronomical observations of his time, and the data was used by his assistant Kepler to derive the laws of planetary motion. No one before Tycho had attempted to make so many planetary observations.


Early years

Tycho was born at his family's ancestral seat of Knutstorp Castlemarker (Danish: Knudstrup borg; Swedish: Knutstorps borg), about eight kilometres north of Svalövmarker in then Danish Scania, now Swedish, to Otte Brahe and Beate Bille. His twin brother died before being baptized. Tycho wrote a Latin ode (Wittendorf 1994, p. 68) to his dead twin, which was printed in 1572 as his first published work. He also had two sisters, one older (Kirstine Brahe) and one younger (Sophia Brahe).

Otte Brahe, Tycho's father, was a nobleman and an important figure at the court of the Danish king. His mother, Beate Bille, came from an important family that had produced leading churchmen and politicians. Both parents are buried under the floor of Kågeröd Church, four kilometres east of Knutstorp. An epitaph, originally from Knutstorp, but now on a plaque near the church door, shows the whole family, including Tycho as a boy.

Tycho later wrote that when he was around age 2, his uncle, Danish nobleman Jørgen Brahe, "without the knowledge of my parents took me away with him while I was in my earliest youth to become a scholar". Apparently, this did not lead to dispute, nor did his parents attempt to get him back. According to one source, Tycho's parents had promised to hand over a boy child to Jørgen and his wife, who were childless, but had not honoured this promise. Jørgen seems to have taken matters into his own hands and took the child away to his own residence, Tosterup Castlemarker. Jørgen Brahe inherited considerable wealth from his parents, which in terms of the social structure of the time made him eligible for a royal appointment as county sheriff. He was successively sheriff to Tranekjærmarker (1542-49), Odensegaard (1549-52), Vordingborg Castlemarker(1552-57), and finally (1555 until his death in 1565) to Queen Dorothea at Nykøbing Castle on Falstermarker.

Tycho attended Latin school from ages 6 to 12, but the name of the school is not known. At age 12, on 19 April 1559, Tycho began studies at the University of Copenhagenmarker. There, following his uncle's wishes, he studied law, but also studied a variety of other subjects and became interested in astronomy. An eclipse on 21 August 1560, especially the fact that it had been predicted, 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, including Sacrobosco's De sphaera mundi, Petrus Apianus's Cosmographia seu descriptio totius orbis and Regiomontanus's De triangulis omnimodis. At age 17, Tycho wrote:

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 realized that progress in the science of astronomy could only be achieved by systematic, and rigorous observation, night after night, using the most accurate instruments obtainable. This program became his life's work. Tycho improved and enlarged existing instruments, and built entirely new ones. His sister Sophia assisted Tycho in many of his measurements. Tycho was the last major astronomer to work without the aid of a telescope, soon to be turned skyward by Galileo and others.

Tycho jealously guarded his large body of celestial measurements, which Kepler "usurped" following Tycho's death.

Brahe's nose

While a student, Tycho lost part of his nose in a duel with Manderup Parsbjerg, a fellow Danish nobleman. This occurred in the Christmas season of 1566, after a fair amount of drinking, while Tycho, who had just turned 20 years old, was studying at the University of Rostock in Rostock, 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. From this event Tycho became interested in medicine and alchemy. For the rest of his life, he was said to have worn a realistic replacement made of silver and gold, using a paste to keep it attached. Some people, such as Fredric Ihren and Cecil Adams have suggested that the false nose also had copper. Ihren wrote that when Tycho's tomb was opened in 24 June 1901 green marks were found on his skull, suggesting copper. Cecil Adams also mentions a green colouring and that medical experts examined the remains. 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 a precious metal one.

Death of his uncle

His uncle and foster father, Jørgen Brahe, died in 1565 of pneumonia after rescuing Frederick II of Denmark from drowning. In April 1567, Tycho returned home from his travels and his father wanted him to take up law, but Tycho was allowed to make trips to Rostock, then on to Augsburgmarker (where he built a great quadrant), Baselmarker, and Freiburgmarker. At the end of 1570 he was informed about his father's ill health, so he returned to Knudstrup, where his father died on 9 May 1571. Soon after, his other uncle, Steen Bille, helped him build an observatory and alchemical laboratory at Herrevad Abbeymarker.

Family life

In 1572, in Knudstrup, Tycho fell in love with Kirsten, daughter of Jørgen Hansen, the Lutheran minister in Knudstrup. She was a commoner, and Tycho never formally married her. However, 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 landholdings. (Skautrup 1941, pp. 24-5)

Kirsten Jørgensdatter gave birth to their first daughter, Kirstine (named after Tycho's late sister, who died at 13) on 12 October 1573. Together they had eight children, six of whom lived to adulthood. In 1574, they moved to Copenhagen where their daughter Magdalene was born. Kirsten and Tycho lived together for almost thirty years until Tycho's death.

Tycho's Moose (Elk)

Tycho was said to own one percent of the entire wealth of Denmark at one point in the 1580s and he often held large social gatherings in his castle. He kept a dwarf named Jepp (whom Tycho believed to be clairvoyant) as a court jester who sat under the table during dinner. Pierre Gassendi wrote from a translation from Gassendi that Tycho also had a tame moose (called an Elk in Europe) and that his mentor the Landgrave Wilhelm of Hesse-Kassel (Hesse-Cassel) asked whether there was an animal faster than a deer. Tycho replied, writing that there was none, but he could send his tame moose. When Wilhelm replied he would accept one in exchange for a horse, Tycho replied with the sad news that the moose had just died on a visit to entertain a nobleman at Landskronamarker. Apparently during dinner the moose had drunk a lot of beer, fallen down the stairs, and died.


Tycho Brahe's grave in Prague, new tomb stone from 1901

Tycho suddenly contracted a bladder ailment after attending a banquet in Prague, and died eleven days later, on 24 October 1601. According to Kepler's first hand account, Tycho had refused to leave the banquet to relieve himself because it would have been a breach of etiquette. After he had returned home he was no longer able to urinate, except, eventually, in very small quantities and with excruciating pain. The night before he died he suffered from a delirium during which he was frequently heard to exclaim that he hoped he would not seem to have lived in vain. Before dying, he urged Kepler to finish the Rudolphine Tables and expressed the hope that he would do so by adopting Tycho's own planetary system, rather than Copernicus's. A contemporary physician attributed his death to a kidney stone, but no kidney stones were found during an autopsy performed after his body was exhumed in 1901, and the modern medical assessment is that it is more likely to have resulted from uremia.

Recent investigations have suggested that Tycho did not die from urinary problems but instead from mercury poisoning—extremely toxic levels of it have been found in hairs from his moustache.

Tycho's body is currently interred in a tomb in the Church of Our Lady in front of Týnmarker, in Old Town Squaremarker near the Prague Astronomical Clockmarker.

Career: observing the heavens

The 1572 supernova

On 11 November 1572, Tycho observed (from Herrevad Abbeymarker) a very bright star, now named 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 (celestial immutability was a fundamental axiom of the Aristotelian world-view), other observers held that the phenomenon was something in the terrestrial sphere below the Moon. However, in the first instance Tycho observed that the object showed no daily parallax against the background of the fixed stars. This implied it was at least farther away than the Moon and those planets that do show such parallax. Moreover he also found the object did not even 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 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 thereby coining the term nova for a "new" star (we now classify this star as a supernova and we know that it is 7500 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" ("Oh thick wits. Oh blind watchers of the sky").

Tycho's discovery was the inspiration for Edgar Allan Poe's poem, "Al Aaraaf." In 1998, Sky & Telescope magazine published an article by Donald W. Olson, Marilynn S. Olson and Russell L. Doescher arguing, in part, that Tycho's supernova was also the same "star that's westward from the pole" in Shakespeare's Hamlet.

Tycho's observatories

Watercolor plan of Uraniborg

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. Upon his return he intended to relocate to Basel, but King Frederick II of Denmark, desiring to keep the distinguished scientist, offered Tycho the island of Hvenmarker in Oresundmarker and funding to set up an observatory. Tycho first built Uraniborgmarker in 1576 (with a laboratory for his alchemical experiments in its cellar) and then Stjerneborg in 1581. Unusual for the time, Tycho established Uraniborg as a research centre, where almost 100 students and artisans worked from 1576 to 1597.

After Frederick died in 1588 and his 11-year old son, Christian IV, succeeded him, Tycho's influence steadily declined. After several unpleasant disagreements, Tycho left Hven in 1597.

He moved to Praguemarker in 1599. Sponsored by Rudolf II, Holy Roman Emperor, Tycho built a new observatory in a castle in Benátky nad Jizeroumarker, 50 km from Prague, and worked there for one year. The emperor then brought him back to Prague, where he stayed until his death. Tycho received financial support from several nobles in addition to the emperor, including Oldrich Desiderius Pruskowsky von Pruskow, to whom he dedicated his famous "Mechanica". 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 supernova of 1572 (sometimes clled Tycho's supernova) and the Great Comet of 1577.

Tycho's observational astronomy

Mural quadrant (Tycho Brahe 1598)

Tycho's observations of stellar and planetary positions were noteworthy both for their accuracy and quantity. His celestial positions were much more accurate than those of any predecessor or contemporary. Rawlins asserts of Tycho's Star Catalog D, "In it, Tycho achieved, on a mass scale, a precision far beyond that of earlier catalogers. Cat D represents an unprecedented confluence of skills: instrumental, observational, & computational—all of which combined to enable Tycho to place most of his hundreds of recorded stars to an accuracy of ordermag 1'!"

He aspired to a level of accuracy in his estimated positions of celestial bodies of being consistently within 1 arcminute of their real celestial locations, and also claimed to have achieved this level. But in fact many of the stellar positions in his star catalogues were less accurate than that. The median errors for the stellar positions in his final published catalog were about 1'.5, indicating that only half of the entries were more accurate than that, with an overall mean error in each coordinate of around 2'. Although the stellar observations as recorded in his observational logs were more accurate, varying from 32.3" to 48.8" for different instruments, systematic errors of as much as 3' were introduced into some of the stellar positions Tycho published in his star catalog due, for instance, to his application of an erroneous ancient value of parallax and his neglect of polestar refraction. Incorrect transcription in the final published star catalogue, by scribes in Brahe's employ, was the source of even larger errors, sometimes by many degrees.

After his death, his records of the motion of the planet Mars provided evidence to support Kepler's discovery of the ellipse and area laws of planetary motion. Kepler's application of these two laws to obtain astronomical tables of unprecedented accuracy (the Rudolphine Tables) provided powerful support for his heliocentric model of the solar system.

Tycho himself was not a Copernican, but proposed a system in which the Sun and Moon orbited the Earth, while the other planets orbited the Sun. 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.

Celestial objects observed near the horizon and above appear with a greater altitude than the real one, due to atmospheric refraction, and one of Tycho's most important innovations was that he worked out and published the very first tables for the systematic correction of this possible source of error. But as advanced as they were, they attributed no refraction whatever above 45 degrees altitude for solar refraction, and none for starlight above 20 degrees altitude.

To perform the huge number of multiplications 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's geo-heliocentric astronomy

In this depiction of the Tychonic system, the objects on blue orbits (the moon and the sun) revolve around the earth.
The objects on orange orbits (Mercury, Venus, Mars, Jupiter, and Saturn) revolve around the sun.
Around all is sphere of fixed stars.

Kepler tried, but was unable, to persuade Tycho to adopt the heliocentric model of the solar system. Tycho believed in geocentrism because he held the Earth was just too sluggish to be continually in motion and also believed that if the Earth orbited the Sun annually there should be an observable stellar parallax over any period of six months, during which the angular orientation of a given star would change. This parallax does exist, but is so small it was not detected until the 1830s, when Friedrich Bessel discovered a stellar parallax of 0.314 arcseconds of the star 61 Cygni in 1838. Tycho advocated an alternative to the Ptolemaic geocentric system, a geo-heliocentric system now known as the Tychonic system. In such a system, originally proposed by Heraclides in the 4th century BC, the Sun annually circles a central Earth (regarded as essentially different from the planets), while the five planets orbit the Sun. In Tycho's model the Earth does not rotate daily, as Heraclides claimed, but is static.

Another crucial difference between Tycho's 1587 geo-heliocentric model and those of other geo-heliocentric astronomers, such as Paul Wittich, Reimarus Ursus, Roslin and Origanus, was that the orbits of Mars and the Sun intersected. This was because Tycho had come to believe the distance of Mars from the Earth at opposition (that is, when Mars is on the opposite side of the sky from the Sun) was less than that of the Sun from the Earth. Tycho believed this because he came to believe Mars had a greater daily parallax than the Sun. But in 1584 in a letter to a fellow astronomer, Brucaeus, he had claimed that Mars had been further than the Sun at the opposition of 1582, because he had observed that Mars had little or no daily parallax. He said he had therefore rejected Copernicus's model because it predicted Mars would be at only two-thirds the distance of the Sun. But he apparently later changed his mind to the opinion that Mars at opposition was indeed nearer the Earth than the Sun was, but apparently without any valid observational evidence in any discernible Martian parallax. Such intersecting Martian and solar orbits meant that there could be no solid rotating celestial spheres, because they could not possibly interpenetrate. Arguably this conclusion was independently supported by the conclusion that the comet of 1577 was superlunary, because it showed less daily parallax than the Moon and thus must pass through any celestial spheres in its transit.

Tychonic astronomy after Tycho

Galileo's 1610 telescopic discovery that Venus shows a full set of phases refuted the pure geocentric Ptolemaic model. After that it seems 17th century astronomy then mostly converted to geo-heliocentric planetary models that could explain these phases just as well as the heliocentric model could, but without the latter's disadvantage of the failure to detect any annual stellar parallax that Tycho and others regarded as refuting it. The three main geo-heliocentric models were the Tychonic, the Capellan with just Mercury and Venus orbiting the Sun such as favoured by Francis Bacon, for example, and the extended Capellan model of Riccioli with Mars also orbiting the Sun whilst Saturn and Jupiter orbit the fixed Earth. But the Tychonic model was probably the most popular, albeit probably in what was known as 'the semi-Tychonic' version with a daily rotating Earth. This model was advocated by Tycho's ex-assistant and disciple Longomontanus in his 1622 Astronomia Danica that was the intended completion of Tycho's planetary model with his observational data, and which was regarded as the canonical statement of the complete Tychonic planetary system.

A conversion of astronomers to geo-rotational geo-heliocentric models with a daily rotating Earth such as that of Longomontanus may have been precipitated by Francesco Sizzi's 1613 discovery of annually periodic seasonal variations of sunspot trajectories across the sun's disc. They appear to oscillate above and below its apparent equator over the course of the four seasons. This seasonal variation is explained much better by the hypothesis of a daily rotating Earth together with that of the sun's axis being tilted throughout its supposed annual orbit than by that of a daily orbiting sun, if not even refuting the latter hypothesis because it predicts a daily vertical oscillation of a sunspot's position, contrary to observation. This discovery and its import for heliocentrism, but not for geo-heliocentrism, is discussed in the Third Day of Galileo's 1632 Dialogo. However, prior to that discovery, in the late 16th century the geo-heliocentric models of Ursus and Roslin had featured a daily rotating Earth, unlike Tycho's geo-static model, as indeed had that of Heraclides in antiquity, for whatever reason.

The fact that Longomontanus's book was republished in two later editions in 1640 and 1663 no doubt reflected the popularity of Tychonic astronomy in the 17th century. Its adherents included John Donne and the atomist and astronomer Pierre Gassendi.

Johannes Kepler published the Rudolphine Tables containing a star catalog and planetary tables using Tycho's measurements.
Hven island appears west uppermost on the base.
The ardent anti-heliocentric French astronomer Jean-Baptiste Morin devised a Tychonic planetary model with elliptical orbits published in 1650 in a simplified, Tychonic version of the Rudolphine Tables. Some acceptance of the Tychonic system persisted through the 17th century and in places until the early 18th century; it was supported (after a 1633 decree about the Copernican controversy) by "a flood of pro-Tycho literature" of Jesuit origin. Among pro-Tycho Jesuits, Ignace Pardies declared in 1691 that it was still the commonly accepted system, and Francesco Blanchinus reiterated that as late as 1728. Persistence of the Tychonic system, especially in Catholic countries, has been attributed to its satisfaction of a need (relative to Catholic doctrine) for "a safe synthesis of ancient and modern". After 1670, even many Jesuit writers only thinly disguised their Copernicanism. But in Germany, Holland, and England, the Tychonic system "vanished from the literature much earlier".

James Bradley's discovery of stellar aberration, published 1729, eventually gave direct evidence excluding the possibility of all forms of geocentrism including Tycho's. Stellar aberration could only be satisfactorily explained on the basis that the Earth is in annual orbit around the Sun, with an orbital velocity that combines with the finite speed of the light coming from an observed star or planet, to affect the apparent direction of the body observed.

Tycho's lunar theory

Tycho's distinctive contributions to lunar theory include his discovery of the Variation of the Moon's longitude. This represents the largest inequality of longitude after the equation of the center and the evection. He also discovered librations in the inclination of the plane of the lunar orbit, relative to the ecliptic (which is not a constant of about 5° as had been believed before him, but fluctuates through a range of over a quarter of a degree), and accompanying oscillations in the longitude of the lunar node. These represent perturbations in the Moon's ecliptic latitude. Tycho's lunar theory doubled the number of distinct lunar inequalities, relative to those anciently known, and reduced the discrepancies of lunar theory to about 1/5 of their previous amounts. It was published posthumously by Kepler in 1602, and Kepler's own derivative form appears in Kepler's Rudolphine Tables of 1627.


Although Tycho's planetary model became discredited, his astronomical observations are considered an essential contribution to the Scientific Revolution. A traditional view of Tycho, originating in the 1654 biography Tychonis Brahe, equitis Dani, astronomorum coryphaei, vita by Pierre Gassendi and furthered by the 1890 biography by Johann Dreyer, which for a long time was considered the most essential work on Tycho, is that Tycho was primarily an empiricist, who set new standards for precise and objective measurements. According to historian of science Helge Kragh, the origin of this view is Gassendi's opposition to Aristotelianism and Cartesianism and it fails to account for the diversity of Tycho's activities.

Tycho considered astrology a subject of great importance, and he was in his own time also famous for his contributions to medicine and his herbal medicines were in use as late as the 1900s. Although the research community Tycho created in Uraniborg did not survive him, while it existed it fulfilled the roles of being both a research center and an important center of education, functioning as a graduate school for Danish as well as foreign students of both astronomy and medicine. Tycho manoeuvred confidently within the political world and his success as a scientist relied on his political skills to ensure funding for his work.

The crater Tychomarker on the Moon is named after him, as is the crater Tycho Brahe on Mars.

He was mentioned also on Warehouse 13 on SyFy, showing what was supposed to be one of his prosthetic noses.

See also


  1. Alena Šolcová: From Tycho Brahe to incorrect Tycho de Brahe..., Acta Universitatis Carolinae, Mathematica et Physica 46, Supplementum, Carolinum, Prague 2005, p. 29–36.
  2. Dansk biografisk Lexikon / II. Bind. Beccau - Brandis (Danish)
  3. Dansk Biografisk Lexikon (Danish Biographical Lexicon). Copenhagen. Gyldendalske Boghandels Forlag, 1887–1905.
  4. J J O'Connor and E F Robertson. Tycho Brahe biography. April 2003. Retrieved 2008-09-28
  5. Cecil Adams. Did astronomer Tycho Brahe really have a silver nose?. 1998-07-17. Retrieved 2008-10-06
  6. Ihren, from a translation
  7. . Page 210 of online version published 2004 covers the moose.
  8. Thoren (1989, p. 468–69)
  9. "Ne frustra vixisse videar!" (Dreyer, 2004, p. 309).
  10. Thoren (1989, p. 469–70)
  11. De stella Nova Photocopy of the Latin print with a partial translation into Danish: "Om den nye og aldrig siden Verdens begyndelse i nogen tidsalders erindring før observerede stjerne..."
  12. Christianson 2000, p. 247
  13. Adam Mosley and the Department of History and Philosophy of Science of the University of Cambridge. Tycho Brahe and Astrology. 1999. Retrieved 2008-10-02
  14. Noel Swerdlow, Astronomy in the Renaissance, pp. 187-230 in Christopher Walker, ed., Astronomy before the Telescope, (London: British Museum Press, 1996), pp. 207-10.
  15. Rawlins 1993, p. 12
  16. Rybka 1984 found a mean error of some 3' for nonbright stars by comparing star Catalogue D with "the modern FK4 star catalogue" values.
  17. Walter G. Wesley, "The Accuracy of Tycho Brahe's Instruments," Journal for the History of Astronomy, 9(1978): 42-53, table 4.
  18. Dennis Rawlins, "Tycho's 1004 Star Catalog", DIO 3 (1993), p. 20, n. 70.
  19. (i)Thoren 1989 Tycho Brahe says: "[the accuracy of the 777 star catalogue C] falls below the standards Tycho maintained for his other activities....the catalogue left the best qualified appraiser of it (Tycho's eminent biographer J.L.E. Dreyer) manifestly disappointed. Some 6% of its final 777 positions have errors in one or both co-ordinates that can only have arisen from 'handling' problems of one kind or another. And while the brightest stars were generally placed with the minute-of-arc accuracy Tycho expected to achieve in every aspect of his work, the fainter stars (for which the slits on his sights had to be widened, and the sharpness of their alignment reduced) were considerably less well located." (ii) Hoskin's 1999 p101 concurs with Thoren's finding "Yet although the places of the brightest of the non-reference stars [in the 777 star catalogue] are mostly correct to around the minute of arc that was his standard, the fainter stars are less accurately located, and there are many errors." (iii) The greatest max errors are given in Rawlins' 1993. They are in descending order a 238 degrees scribal error in the right ascension of star D723; a 36 degrees scribal error in the right ascension of D811 (p42); a 23 degrees latitude error in all 188 southern stars by virtue of a scribal error (p42 M5); a 20 degrees scribal error in longitude of D429; and a 13.5 degrees error in the latitude of D811.
  20. Stephenson (1987, pp. 22, 39, 51, 22, 204).
  21. According to Gingerich and Linton (2004, p. 224) these tables were some 30 times more accurate than other astronomical tables then available.
  22. Swerdlow (2004, p. 96), Stephenson (1987, 67–68)
  23. Thoren 1989 Tycho Brahe p14-15 T & W 1989
  24. J J O'Connor and E F Robertson. Bessel biography. University of St Andrews. Retrieved 2008-09-28
  25. See the three articles by Thoren, Jarell and Schofield in Wilson & Taton 'Planetary astronomy from the Renaissance to the rise of astrophysics' 1989 CUP for details
  26. Ibid
  27. See p178-80 of Dreyer's 1890 'Tycho Brahe'
  28. See p171 The Wittich Connection Gingerich and Westman 1988
  29. Taton & Wilson 1989
  30. See p345-56 of Stillman Drake's 1967 Dialogue concerning the two chief world systems. But see Drake's Sunspots, Sizzi and Scheiner' in his 1970 Galileo Studies for its critical discussion of Galileo's misleading presentation of this phenomenon.
  31. Taton & Wilson (1989, pp. 42, 50, 166).
  32. See page 41 in Christine Schofield, The Tychonic and Semi-Tychonic World Systems, pages 33-44 in R Taton & C Wilson , The General History of Astronomy, Vol.2A.
  33. See page 43 in Christine Schofield, The Tychonic and Semi-Tychonic World Systems, pages 33-44 in R Taton & C Wilson , The General History of Astronomy, Vol.2A.
  34. V E Thoren, "Tycho and Kepler on the Lunar theory", Publications of the Astronomical Society of the Pacific, vol.79 (1967), pp. 482-489.
  35. Kragh, pp. 220–22
  36. See e.g. Kragh, pp. 234–41.
  37. Kragh, p. 243.


Opera omnia

  • Brahe, Tycho. Tychonis Brahe Dani Opera Omnia (in Latin). Vol 1-15. 1913–1929. Edited by J. L. E. Dreyer.
  • Brahe, Tycho. 'Astronomiæ instauratæ mechanica', 1598 European Digital Library Treasure
  • Hoskin, M. (Ed.) The Cambridge Concise History of Astronomy CUP 1999
  • Olson, Donald W.; Olson, Marilynn S.; Doescher, Russell L., "The Stars of Hamlet," Sky & Telescope (November 1998)
  • Pannekoek, A. A History of Astronomy Allen & Unwin 1961
  • Pledge, H. Science since 1500 1939
  • Rybka, P. Katalog Gwiazdowy Heweliusza, Warsaw 1984.
  • Skautrup, Peter, 1941 Den jyske lov: Text med oversattelse og ordbog. Aarhus: Universitets-forlag.
  • Swerdlow, N. M. Astronomy in the Renaissance in Walker 1996
  • Thoren, V. Tycho Brahe in Taton & Wilson CUP 1989
  • Walker, C. (Ed.) Astronomy before the telescope British Museum Press 1996
  • Wesley, W. G. "The Accuracy of Tycho Brahe's Instruments," Journal for the History of Astronomy, 9 (1978)
  • Wittendorff, Alex. 1994. Tyge Brahe. Copenhagen: G. E. C. Gad.

Further reading

  • Kitty Ferguson: The nobleman and his housedog: Tycho Brahe and Johannes Kepler: the strange partnership that revolutionised science. London: Review, 2002 ISBN 0-7472-7022-8 (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
  • Arthur Koestler: The Sleepwalkers: A History of Man's Changing Vision of the Universe. Hutchinson, 1959; reprinted in Arkana, 1989
  • Godfred Hartmann: Urania. Om mennesket Tyge Brahe. Copenhagen: Gyldendal, 1989 ISBN 87-00-62763-1
  • Wilson & Taton Planetary astronomy from the Renaissance to the rise of astrophysics 1989 CUP (articles by Thoren, Jarell and Schofield on the nature and history of the Tychonic astronomical model)
  • (analysis of individual instrument accuracies)
  • (critical analysis of Tycho's 1004 star catalogue D. Printing date: 2009\1\12)

External links

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