1.9 The Life and Times of Georg von Peuerbach

Whitney Webb

Mr. Percival

Astronomy Honors

10 Oct. 2007

Georg von Peuerbach

Considered to be the first modern astronomer, Georg von Peuerbach contributed greatly to the fields of Astronomy and Mathematics during the Late Middle Ages. Born the son of Ulrich Aunpekh in 1423, he grew up in the small Austrian town of Peuerbach. His early life is unknown as the first details of his life were recorded following his enrollment at the University of ViennaEurope, but few record remains of the actual dates. By this time, Peuerbach was already internationally known as an astronomer despite having no publications at the time. He lectured throughout Europe, which allowed him to several important astronomers of the time, such as Giovanni Bianchini. Upon his return, he received his Master’s Degree in Mathematics and began teaching at the university. During this time, Peuerbach met Regiomontanus, who would later become Peuerbach's collaborator and most celebrated pupil. in 1446. Interestingly, he was enrolled under the name Georgius Aunpekh de Pewrbach, but later records of his life commonly use variations of Peuerbach as his surname. At the university, he studied Mathematics and taught himself Astronomy. Although no Astronomy teacher existed at the university, it had several instruments and a library to which Peuerbach had access. Between 1448 and 1453 he traveled throughout

Regiomontanus first began collaborating with Peuerbach in 1453 when he was sixteen years old. Until Peuerbach’s death eight years later, they collaborated extensively, resulting in several important astronomical observations and publications. In 1454, Peuerbach published his first work, Theoricae Novae Planetarum, which presented Ptolemy’s complicated epicycle theory in a simple, but thorough manner. Peuerbach believed that the planets were in solid crystalline spheres, yet believed that their motions were controlled by the Sun. This work, Peuerbach’s most important, was an attempt to bring together Aristotelian and Ptolemaic theory, causing Peuerbach’s work to remain the basis of academic instruction in Astronomy until Copernicus. This publication demonstrates that Peuerbach used techniques developed by Islamic astronomers in modifying Ptolemy’s model. Additionally, Peuerbach observed what came to be known as Halley’s Comet and recorded his observations in 1456. He would make several other observations of comets throughout his life. In 1457, Regiomontanus and Peuerbach observed a lunar eclipse, measuring its duration and the time of the midpoint. It was found that the eclipse occurred eight minutes earlier than previously calculated tables predicted. Due to this discrepancy, Peuerbach produced a new collection of tables of eclipse calculation which he completed in 1459. When he observed several eclipses the following year, he compared their times to his predictions, which showed tremendous accuracy. Many of his astronomical observations were made at the Observatory of Varadinum in Transylvania.

Due to the inextricable link between astrology and Astronomy during the Middle Ages, Peuerbach’s reputation earned him the prestigious position of court astrologer for King Ladislas V of Hungary and Bohemia in 1454. However, the position was short-lived as political turmoil in Prague caused Ladislas to flee the country. He died a year later in 1458. Peuerbach did not become court astrologer for either of Ladislas’s successors, but was instead appointed to the court of the Holy Roman emperor Frederick III, a position he retained until his death in 1461. During this period, he constructed several celestial spheres. He also furthered his studies in Mathematics, writing on the computations of sine and chords as well as integers and fractions. His table of sines was his most impressive mathematical work as it calculated sines for every minute of arc for a radius of six hundred thousand units. Also, his use of Arabic numerals in his table of sines is believed to have furthered the advancement of Mathematics and to have helped introduce these numerals into the Western study of Mathematics. Peuerbach is also credited with the invention of several scientific instruments such as the regula, or geometrical square.

Despite his short life, Georg von Peuerbach accomplished much for both the fields of Astronomy and Mathematics. He published twenty known works and greatly influenced the ideology of the time in regards to planetary motion. His pupil, Regiomontanus, became a successful astronomer in his own right, largely due to the teaching and mentoring of Peuerbach. Furthermore, his works in Trigonometry and Geometry are extremely important. In fact, Peuerbach is credited with being one of the first to introduce sines into Trigonometry. Peuerbach’s many scientific and mathematic achievements have created him a noteworthy legacy as the first modern astronomer. It is because of this legacy that the Purbach crater on the Moon carries his namesake.

Works Cited

Bress, Thomas. "George von Peuerbach." The Catholic Encyclopedia. 1911. Robert Appleton Company. 10 Oct 2007 .
Knight, Judson. "Georg von Peuerbach." Science and Its Times. Ed. Neil Schlager and Josh Lauer. Vol. 2: 700 to 1449. Detroit: Gale, 2001. 230-231.
O'Connor, J. "Georg Peurbach." 01 Aug 2006. University of St. Andrews. 10 Oct 2007 .