The greatest astronomer of the pre-telescope era: Who is Tycho Brahe?

(1546-1601) Danish astronomer. He was the greatest astronomer of the pre-telescope era, with his observations of comets and novae, particularly his robust measurements of the position of Mars. He was born on December 14, 1546, in Knudstrup in Skane (Sweden), which was then part of the Kingdom of Denmark. The great landowner was the son of a noble family. Since he had no children, he received a good education in the castle of his uncle, who adopted him when he was only a few months old and learned Latin at the age of seven. It is not known when he changed his Danish name to Tyge, but from his age to the present day it has been called Tycho rather than a surname.

Tycho, who studied philosophy and theology at the Lutheran University of Copenhagen between 1559 and 1562, as well as Latin and Greek literature, rhetoric, and basic sciences, most likely developed Aristotle's Physica, Euclid's Stoicbea and Ptolemy's geocentric model of the universe during this period. he recognized. Later, his uncle, following the tradition of the age, sent Tycho to Leipzig University in 1562 to study law like all nobles. While he was studying law at this university during the day until 1565, Tycho, who started to observe the stars secretly at night, returned to Denmark that year.

However, after the death of his uncle, who raised him, and no one in his family except one of his uncles showed interest in his scientific studies, he moved to Germany again. At that time, he lived with an artificial metal nose until he died when the tip of his nose was cut off during a duel. Tycho, who studied at the University of Rostock from 1566 to 1568 and at the University of Basel for about a year, remained in Augsburg until 1570, continuing his astronomy studies and observations. When he learned that his father was sick, he returned to his country; With the death of his father a year later, the land of Knudstrup was inherited by two brothers. However, Tycho would not stay in his father's house but would settle in his uncle's castle, who was interested in his work and would make his first major astronomical observation there in 1572.

Beginning in 1574, he taught at the University of Copenhagen for about a year, then traveled around Germany, met with astronomers, and studied observing instruments. Meanwhile, he was looking for the opportunity to comfortably continue his observations under the protection of a king or a prince. The support he expected came from King Frederik II of Denmark and Norway. In February 1576, a few months after his return, the king donated the island of Hven, off Copenhagen, to Tycho, without sparing the necessary money to establish an observatory there. On the other hand, Tycho, who was the chief astrologer of the royal family, maintained good relations with the palace and made his best observations on the island of Hven for twenty years. However, after the death of Frederik II in 1588, his son, IV. Christian was not as generous to Tycho as his father; astronomy: cut the income of Tycho and his observatory, disapproving of large investments in his observations. Tycho, who lost his former prestige in the palace, left the island of Hven, which had been donated to him for life and settled in Copenhagen in 1597. He dedicated his work Mechanica, which he wrote at that time, to Rudolf II of the Habsburg dynasty, and the emperor invited him to Prague, stating that he would support his observations. Thereupon, Tycho, who went to Prague in 1599, settled in the Benatky castle, which was given to him by the emperor, near the city and began his observations again. In February 1600, Kepler arrived in Prague to work with Tycho. However, this mighty fruitful collaboration did not last long, and Tycho Brahe died in Prague on October 24, 1601, leaving the task of completing and publishing his final work to Kepler.

The first natural phenomenon that attracted Tycho's attention to astronomy was the solar eclipse on August 21, 1560; He was a student at the University of Copenhagen at the time and was fascinated by the fact that the eclipse was actually observed on the foretold. He made a copy of Stadius' ephemeris and began to study astronomy on his own, continuing this interest at the University of Leipzig, where he was later sent. It was a real turning point in Tycho's life when he observed the conjunction of Saturn and Jupiter in August 1563 with very simple tools at his disposal. Tycho, who determined the time when these two planets would be closest to each other by calculating the positions of these two planets from the astronomical tables, saw that there was a one-month error between his calculations and the date he observed the conjunction, and he decided that the ancient astronomical tables and ephemeris should be rearranged with more precise observations. This observation was his first important observation, in which he wrote down his data, calculations, and results; Continuing his observations with the tools he developed after 1564, Tycho pioneered a new era in astronomy based entirely on mathematics, healthy observations, and measurements instead of assumptions.

Tycho, who was interested in chemistry while he was in Augsburg, set up a laboratory and started chemistry experiments when he settled in his uncle's castle in Herritzwad in 1571. However, this new pursuit came to an abrupt end on November 11, 1572; when he looked up at the sky that night, a new star in the constellation Cassiopeia (The Armchair) caught his attention with a brightness he had never seen before. He constantly watched this star, which he named with the Latin word nova, meaning new, until it disappeared in March 1574; he measured the angular distance of the new star from the other stars in Cassiopeia with great precision with a sextant he had made; its color changes from white to yellow, then red, and its brightness is -1. observed it decreasing from magnitude 6 to magnitude 6 (in light of these data, this star is now known to be an exploding supernova type). Aristotle understood that these color and brightness changes are not an atmospheric illusion caused by the reflection or refraction of light, and since it does not give the smallest parallax, this new star will not be as close to the Earth as the Moon, and since it does not move in the opposite direction to the daily circulation, Aristotle He concluded that it could not be found in the planetary spheres he described. Nor could it be a comet; because it had no tail and did not move like comets. He finally explained that this nova was located in the outermost celestial sphere, where the other fixed stars were, and was a star like them, as far from Earth as any other fixed star. This phenomenon, which he first described in his short review De nova stella (“On the New Star”) published in 1573, and which he examined in detail in the Astronomer la instauratae progymnasmata, published posthumously, supported the view of Aristotle, who claimed that nothing would change in the sphere of stars outside the sky. it was inconsistent. When the observations of other astronomers confirmed Tycho's findings, it was necessary to reconsider Aristotle's cosmology.

After these observations, 4 Tycho, whose fame gradually spread, found the support he expected to establish a large observatory, and he chose the highest point of the island of Hven, donated by the king, and started the construction of the observatory, which he named Uraniborg ("Heaven Castle"). Uraniborg, whose main building was completed in 1580 and spread over a wide area with its annexes, was both Tycho's home and the most famous and most magnificent observatory of its age for twenty-one years from 1576 to 1597. Indeed, it was one of a kind with its workshops where observation instruments were made, a small chemistry laboratory, library, food warehouses, a nursing home added in 1584, and a paper mill completed in 1592. Tycho's main observation tools, who built another observatory named Stjerneborg ("Castle of Stars") next to Uraniborg in 1584, were sextants measuring the angular distance, elevation, meridian crossing, and zenith distance of celestial bodies, a small astrolabe, an observatory mounted on it. It was a large rotating sphere that could be rotated in all directions, and a quadrant (quatrain) about 3.5 m in diameter, hung on the wall. These tools were neither too advanced nor too precise; however, with these meticulously graded instruments, Tycho was able to make the most precise measurements before the telescope's use, with an error of less than one-tenth of a one-degree circular arc.

During his observations at Uraniborg, Tycho observed a large comet with a very long tail just after sunset on November 13, 1577. The statement that this comet followed a path from west to east, and that the tail-like formation was due to the sun's rays passing through the star's head region, also refuted Aristotle's theory about comets. Thus, after the nova observations in 1572 and the comet observations in 1577, Tycho, who felt the need to define a new universe, developed his own earth-day-centered universe model. In his lectures at the University of Copenhagen in 1574, he defended Ptolemy's geocentric model from the physical side and Copernicus' heliocentric universe model from the mathematical side, but he did not fully adopt either of them. As a matter of fact, Tycho's model of the universe is a mixed model that tries to reconcile the systems of Ptolemy and Copernicus: As in the Ptolemaic system, the Earth is still fixed at the center of the universe; The Moon said, “The sun and the outer planets also revolve around it; On the other hand, the inner planets (Mercury and Venus) between the Earth and the Sun are centered on the Sun, as in the Copernican system. This model, which he explained in the Progymnasmata and which Stjerneborg had drawn on his ceiling, is of only historical significance today as the counter-option of the Ptolemaic system and an intermediate stage that facilitated the adoption of the Copernican model.

Tycho was an observer who believed in the importance of astrology. While in Rostock, he interpreted the lunar eclipse of 28 October 1566 as a sign foreshadowing the death of Suleiman I (Kanuni), who had set out on the Zigetvar expedition, but later learned that the sultan had died a month and a half before the eclipse. Tycho, who aimed to determine the positions of the fixed stars and the movements of the Sun, Moon, and planets in his observations in Hven, determined the irregularities in the latitude and longitude motion of the Moon and its oscillation on the orbit and determined its position relative to the known fixed stars. These measurements and a catalog giving the position of 777 fixed stars are collected in Progymnasmata. Tycho increased the number of these stars to 1,000 to prepare a richer catalog and his new protector, II. He intended to present it to Rudolf. He could not fulfill this request, as his work in Prague resulted in his premature death, but before he died he asked Kepler to finish this catalog as soon as possible. Published in 1627 and known as Rudolf's Tables, the work is largely based on Tycho's observations, with additions by Kepler.

The disagreement between Kepler and Tycho, who came to Prague on February 3, 1600, to work with Tycho and was the biggest defender of Copernicus' heliocentric theory, made their joint work very difficult. Tycho, who was working on the orbital motion of Mars at the time, asked Kepler to verify his system and publish it to everyone until the last moment. Although Kepler developed a theory contrary to Tycho's model based on Copernicus' system, he never denied that Tycho prepared his laws regarding planetary orbits, which is considered the beginning of modern astronomy, by using Mars observations.