Georg von Peuerbach
Georg von Peuerbach was a prominent Austrian astronomer and scholar, born in Upper Austria, whose early life remains largely undocumented except for his father's name. He enrolled at the University of Vienna in 1446, where he began his studies in astronomy, likely influenced by the teachings of John of Gmunden. Peuerbach traveled extensively across Europe, engaging with various scholars and accepting positions as a court astrologer, ultimately serving King László V of Hungary and later the Holy Roman Emperor. His work significantly contributed to the revival of classical learning at his university through lectures on Latin literature and humanistic studies.
Peuerbach is renowned for his influential textbooks, notably "Theoricae novae planetarum," which clarified Ptolemaic astronomy and introduced new theories regarding planetary motion. He also advanced astronomical tools and methods, including the construction of sundials and the calculation of comet dimensions. His collaboration with Johann Müller, known as Regiomontanus, led to significant astronomical observations and the development of more accurate astronomical tables. Peuerbach's use of Arabic numerals and emphasis on sines laid foundational work for future mathematicians and astronomers, making him a key figure in the transition from medieval to modern science. His legacy continued to influence scholars well into the sixteenth century, providing critical resources for the study of astronomy.
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Georg von Peuerbach
Austrian mathematician and astronomer
- Born: May 30, 1423
- Birthplace: Peuerbach, Austria
- Died: April 8, 1461
- Place of death: Vienna, Austria
A pre-Copernican astronomer, Peuerbach accepted, reintroduced, and extended the ideas of Ptolemy and made original astronomical observations. His published works include a look at new theories of the planets, which became a standard astronomy textbook, and an aid for the calculation of eclipses.
Early Life
Georg von Peuerbach (gay-awrg fawn PEWR-bahk) was born in Upper Austria. Other than his father’s name, Ulrich, nothing is known about his early years. In 1446, he entered the University of Vienna with the name Georgius Aunpekh de Pewrbach, and earned a bachelor’s degree in 1448. By this time, he had probably already begun the study of astronomy under the followers of John of Gmunden (d. 1442).
Between 1448 and 1453, Peuerbach traveled to several countries, including France, Germany, and Italy, and lectured in Padua and Ferrara. In Ferrara, he met the most important contemporary Italian astronomer, Giovanni Bianchini, who tried to convince him to teach at an Italian university; Peuerbach had been given offers to teach at Bologna and Padua. In his later years, Peuerbach knew Nicholas of Cusa, and it is possible that he met him in Rome during this period. Peuerbach received a master’s degree from the University of Vienna in 1453. Around this time, he became the teacher and colleague of Johann Müller, known as Regiomontanus.
From 1453 to 1456, Peuerbach corresponded with the imperial astrologer to Holy Roman Emperor Frederick III, in Wiener Neustadt. With the astrologer’s encouragement, the impoverished Peuerbach accepted in 1454 the position of court astrologer to King László V of Hungary, and later became the imperial astrologer.
While Peuerbach’s service to king and emperor employed his knowledge of astronomy and astrology, his contribution to the University of Vienna involved Humanistic studies. He was among the scholars who brought the revival of classical learning to the University of Vienna by lecturing on Vergil’s Aeneid (c. 29-19 b.c.e.), on Juvenal, and possibly on Horace, and by participating in a disputation on the art of oratory and poetics in 1458. Scholars believe that Peuerbach was the author of a treatise on letter writing. He also wrote poetry in Latin.
Life’s Work
Peuerbach’s correspondence with Nihil reveals that during the 1450’s, Peuerbach engaged in the construction of horseshoe-shaped sundials with magnetic needles, the making of almanacs necessary for his astrological work and the interpretation of comets. For his almanacs, Peuerbach revealed that he had mastered the use of the thirteenth century Alfonsine tables, the first set of astronomical tables in Europe, to determine planetary positions and movement and that he was learning to use the newer tables of Bianchini. Twenty works by Peuerbach are known.
With the 1456 appearance of Halley’s comet, Peuerbach became the first to attempt to calculate the length of a comet’s tail and a comet’s diameter. His results 4 German miles (one German mile equals 25,000 feet, or 7,620 kilometers) for the diameter and 80 German miles for the tail were erroneous, however, because he based them on the doubtful values for the diameter of Earth and the distance of the Moon computed by Ptolemy (c. 100-c. 178) and Archimedes (c. 287-212 b.c.e.). This work provided inspiration for Regiomontanus and sixteenth century astronomers to produce additional important works about comets.
Peuerbach contributed also to the measurement of space and time. Among the instruments on which he wrote papers were the astrolabe quadrant, the astrolabe, a sundial with gnomon, and the geometric square, a device to measure the heights of constellations and other distant terrestrial objects. The geometric square had rods forming a square, with 1,200 gradations on two of the rods and movable points with a sighting hole. He also invented an instrument to represent the true new moon.
Much of Peuerbach’s work involved direct observations. He revised the latitude of Vienna, setting it at 48.22°, closer to the modern value of 48.12°. With Regiomontanus, he observed a lunar eclipse in 1457 and two in 1460. As calculations based on the Alfonsine tables gave an incorrect midpoint for the 1457 eclipse, Peuerbach reorganized and expanded the tables to facilitate computations greatly. Finished around 1459 and available in manuscript form, the work was edited and published in 1514 as Tabulae eclipsium super meridiano Viennensi (tables of eclipses above the Viennese meridian). Astronomers throughout the sixteenth century recognized the monumental efforts put into the work. Peuerbach and Regiomontanus used the Tabulae eclipsium super meridiano Viennensi to determine the eclipses of 1460.
Peuerbach was the author of an extremely important textbook based on Ptolemy’s second century Earth-centered astronomy, Theoricae novae planetarum (English translation, 1987), published by Regiomontanus in 1474. The standard text until this time had been the anonymously written Theorica planetarum communis (thirteenth century; theory of the planets). The topics covered in Peuerbach’s text covering new theories of the planets include the Sun, Moon, superior planets, Venus, Mercury, eclipses, the theory of latitude, and the motion of the eighth sphere based on the Alfonsine tables. As an elementary work, it provided many definitions of technical terms. In this work, Peuerbach attempted to reconcile two conceptions explaining the motion of the planets: the planet-bearing crystalline spheres, which Ptolemy accepted in Hypotheseis ton planomenon (planetary hypotheses) and the epicycle/deferent system of Ptolemy. He presented a model of the solid spheres based on the work of the Arab mathematician and astronomer, Alhazan (965-1039). These spheres remained part of the astronomical tradition until disproved by Tycho Brahe .
Peuerbach also explained the particular motions of the planets according to Ptolemy’s epicycles. It may also be pointed out the Peuerbach suggested that the Sun controlled the motions of the planets and thus anticipated the new role the Sun acquired during the scientific revolution.
Another major work was Peuerbach’s abridgment of Ptolemy’s Mathē;matikē; suntaxis (c. 150; better known as Almagest, 1952). In 1460, Cardinal Bessarion, a Greek scholar and Catholic Church official, invited Peuerbach to prepare an epitome of the Almagest, that is, a short, understandable translation with explanatory comments, which was called Epitoma magesti Ptolemaei (1496). Peuerbach knew Gerard’s Latin translation almost by memory, but insisted on the aid of Regiomontanus, who knew Greek and could work with the original. Peuerbach had finished six of the thirteen books when he died at age thirty-seven, having obtained a promise from Regiomontanus to complete the translation. Regiomontanus completed it by 1463 and died in 1476. The epitome was first published in 1496 with many errors, but better editions appeared in 1543 and 1550.
Other contributions include Peuerbach’s work in mathematics. He wrote a short treatise on the computation of sines and chords. In another work, he presented computations of sines at intervals of ten minutes. Following the work of Arab scholars, he recognized for astronomical calculations the superiority of using sines rather than chords, which Ptolemy had used. Finally, he produced a popular elementary mathematical book on computation using integers and fractions, a book that was printed several times in the late fifteenth and early sixteenth centuries. Peuerbach is also noted for using Arabic numerals, which were still not universally employed in the fifteenth century.
Significance
Peuerbach’s work clarified Ptolemy’s astronomy and helped to bring consistency to the work of Peuerbach’s contemporaries. His influence continued until after Copernicus began the revolution that overturned Ptolemaic, Earth-centered astronomy.
His Theoricae novae planetarum and Epitoma magesti Ptolemaei provided contemporary scholars with definitions of technical terms employed until the early seventeenth century. Theoricae novae planetarum went through fifty-six editions by 1650 and was the subject of numerous commentaries.
To the time of Galileo and Kepler, scholars, including Copernicus, relied on the Epitoma magesti Ptolemaei as the basic treatise on Ptolemy’s astronomy. Finally, astronomers used his tabulae well into the sixteenth century, when new astronomical tables were prepared.
Peuerbach represents the use of Arabic learning in the West because he worked with Arabic numerals in computing sines, and he adopted the crystalline spheres of the Alfonsine tables.
Bibliography
Aiton, E. J. “Pürbach’s Theoricae novae planetarum: A Translation with Commentary.” Osiris (2d series) 3 (1987): 4-43. A short description of Peuerbach’s life that introduces the translation of his important theory of the planets, including drawings of planetary motions.
Dobrzycki, J., and R. L. Kremer. “Pürbach and Maragha Astronomy? The Ephemerides of Johannes Angelus and Their Implications.” Journal of the History of Astronomy 27, no. 3 (1996): 187-237. Argues that Peuerbach was familiar with Arab astronomy and that it influenced his work.
Margolis, Howard. It Started with Copernicus: How Turning the World Inside Out Led to the Scientific Revolution. New York: McGraw-Hill, 2002. Chapter 1 covers pre-Copernican astronomy, based on Ptolemy, on which Peuerbach’s new theory of the planets was highly influential.
North, John. The Norton History of Astronomy and Cosmology. New York: W. W. Norton, 1995. An excellent history of astronomy, useful again for a discussion of Peuerbach’s influence.
Zinner, Ernst. Regiomontanus: His Life and Work. Translated by Ezra Brown. New York: North-Holland, 1990. A biography of Peuerbach’s teacher, Johannes Müller, also known as Regiomontanus, which provides details about Peuerbach’s life and work as well.