Michael Maestlin
Michael Maestlin was a German astronomer and mathematician, best known as the mentor of Johannes Kepler. A student of Philipp Apian, Maestlin is recognized as the teacher who had the greatest influence on Kepler. He is regarded as one of the most significant astronomers of the period between Copernicus and Kepler.
Early life and family
Maestlin was born on 30 September 1550 in Göppingen, a small town in southern Germany located about 50 kilometers east of Tübingen. The son of Jakob Maestlin and Dorothea Simon, he was born into a Protestant family. Maestlin had an older sister named Elisabeth and a younger brother named Matthäus.His family’s original surname was Leckher or Legecker, and they lived in the village of Boll, a few kilometers south of Göppingen. In his autobiography, Maestlin recounts how the family name Legecker was changed to Mästlin. He explains that one of his ancestors received the nickname after an old blind woman touched him and exclaimed, "Wie bist du doch so mast und feist! Du bist ein rechter Mästlin!" This roughly translates to, "How are you so large and plump? You are truly a fatso!"
Maestlin married Margarete Grüniger on 9 April 1577. While little information is available about his children from this marriage, it is known that he had at least three sons—Ludwig, Michael, and Johann Georg—and at least three daughters—Margareta, Dorothea Ursula, and Anna Maria. In 1588, Margarete died at the age of 37, possibly due to complications from childbirth. This untimely loss left several children under Maestlin's care and may have influenced his decision to remarry the following year.
In 1589, Maestlin married Margarete Burkhardt. Together, they had eight children. In a letter to Johannes Kepler written that same year, Maestlin shared how deeply troubled he was by the death of his month-old son, August.
Education
In 1565, at around 15 years of age, Maestlin was sent to the nearby Klosterschule in Königsbronn. In 1567, he transferred to a similar school in Herrenalb. After completing his education there, Maestlin enrolled at the University of Tübingen, matriculating on 3 December 1568. In 1569, he entered the university as a recipient of a scholarship from the Duke of Württemberg.Maestlin studied theology at the Tübinger Stift, an elite educational institution founded in 1536 by Duke Ulrich von Württemberg. He earned his Baccalaureate in 1569 and his master's degree in 1571. After obtaining his master's degree, Maestlin remained at the university as both a theology student and a tutor in the seminary church in Württemberg.
Letters concerning Maestlin’s academic qualifications reveal that he graduated summa cum laude, ranking third in a graduating class of twenty. During his studies, Maestlin was taught by Philipp Apian, though the exact courses he took remain uncertain. It is believed Apian taught topics such as Frisius's Arithmetic, Euclid's Elements, Proclus's Sphera, Peurbach's Theoricae Novae Planetarus, and the use of geodetic instruments.
Apian’s teachings appear to have influenced Maestlin’s work, particularly his paper on sundials, which includes structured elements of celestial globes and maps.
In 1584, Maestlin was appointed Professor of Mathematics at the University of Tübingen. He served as Dean of the Arts Faculty during the following terms: 1588–89, 1594–95, 1600–01, 1607–09, 1610–11, 1615, 1623, and 1629. Maestlin primarily taught trigonometry and astronomy, and it is highly likely that he used his book, Epitome Astronomiae, as a reference in his lectures.
In 1576, Maestlin was appointed as a deacon at the Lutheran church in Backnang, a town about 30 kilometers northwest of Göppingen. While there, he observed the comet of 1577. Tycho Brahe, observing the same comet from Denmark, used parallax measurements to determine that the comet was located beyond the Moon, contradicting the astronomical theories of Aristotle and Ptolemy. Maestlin independently arrived at a similar conclusion and, within the framework of the Copernican system, proposed that the comet resided in a region between the spheres of Venus and the Earth-Moon system. From 1577 to 1580, Maestlin also served as the chief scientific adviser to the Duke of Württemberg.
Career
In 1580, Maestlin became a professor of mathematics, first at the University of Heidelberg, and later at the University of Tübingen, where he taught for 47 years starting in 1583. In 1582, he authored a popular introduction to astronomy.While teaching at the university, Maestlin primarily taught traditional Ptolemaic astronomy in his courses. However, he introduced Copernican heliocentric astronomy to his advanced students, fostering a deeper understanding of the revolutionary model.
While Maestlin had diverse interests, including calendar reform and mathematics, he was, above all, an astronomer. He dedicated much of his research to studying the Sun, the Moon, and eclipses. His 1596 work, Disputatio de Eclipsibus, focuses almost entirely on the Sun and the Moon and is frequently referenced in Kepler's 1604 work, Astronomiae Pars Optica.
In 1587, Maestlin published a manuscript titled Tabula Motus Horarii, which provides the daily motion of the Sun in hours and minutes, along with its positions in two-minute intervals. He also published other tables that present equivalent information in degrees, minutes, and seconds.
Among Maestlin's students was Johannes Kepler, who regarded him not only as a teacher but also as a lifelong mentor. Although Maestlin primarily taught the traditional geocentric Ptolemaic model of the Solar System, he was one of the earliest proponents of the heliocentric Copernican view and introduced it to his advanced students.
Maestlin frequently corresponded with Kepler and played a significant role in influencing his adoption of the Copernican system. Additionally, Maestlin's work is credited with contributing to Galileo Galilei's acceptance of heliocentrism.
The first known calculation of the golden ratio as a decimal, approximately 0.6180340, was made by Maestlin in 1597. He included this calculation in a letter to Kepler about the Kepler triangle.
Maestlin was one of the few astronomers of the 16th century to fully embrace the Copernican hypothesis, which proposed that the Earth was a planet that moved around the Sun. In 1570, he acquired a copy of Copernicus' seminal work, De revolutionibus orbium coelestium.
In his notes, Maestlin responded to the concept of distant stars revolving around a fixed Earth every 24 hours. He also shared everything he could about Copernicus' work with Kepler.
In accepting the Copernican view of the Solar System, Maestlin believed that the "movement of commutation" of the superior planets—those farther from the Sun than Earth—and the lack of parallactic motion in the supernova meant that the supernova must have occurred outside the planetary spheres, in the realm of fixed stars. This contradicted the previous understandings of the Ptolemaic and Aristotelian models.
Maestlin also concluded that the nova provided evidence for the heliocentric Solar System. He argued that unless people concede that comets can exist in the stellar orb, which has an immense altitude and an unknown extent, the distance between the Sun and the Earth, as described by Copernicus, remains incomparable.
In 1589, Maestlin published a dissertation on the fundamental principles of astronomy and the first edition of his book Epitome Astronomiae. Epitome Astonomiae went through six editions and used works such as Ptolemy's famous geocentric model to create detailed descriptions of astronomy.
The preface to the 1596 republication of Georg Joachim Rheticus' Narratio Prima was written by Maestlin. This preface served as an introduction to the work of Copernicus.
In 1613, Maestlin acquired his first set of telescopes. In a letter to Kepler, Maestlin mentioned that he was unable to observe the satellites of Saturn or the phases of Venus; however, he was able to see the moons of Jupiter.
SN 1572 supernova
In November 1572, Maestlin and many others around the world witnessed a strange light in the sky, which we now know was a galactic supernova. This Type Ia supernova, known as SN 1572, occurred in the constellation Cassiopeia and was the first galactic supernova to be observed in Europe.Maestlin attempted to explain this phenomenon in his tract Demonstratio astronomica loci stellae novae, tum respectu centri mundi, tum respectu signiferi & aequinoctialis. This short mathematical and astronomical appendix, which detailed the supernova, was published in Tübingen in March or April of 1573.
Maestlin's treatise attracted the attention of Tycho Brahe, who reproduced it in its entirety, along with his own criticisms, in one of the best-known publications on the subject, his posthumously printed Astronomiae instauratae progymnasmata. Maestlin's treatise is available in manuscript form in Stuttgart and Marburg.
Maestlin's treatise on the nova of 1572 featured many aspects remarkably similar to Tycho de Brahe's much longer treatise on the same nova, titled De Stella Nova. Both treatises were published in 1602, although Maestlin's was believed to have been written much earlier. In his work, Maestlin focused extensively on the mathematics behind determining the exact location of the new star.
Great comet of 1577
In accordance with the Copernican view of the heavens, Johannes Kepler calculated that there were empty spaces between the planetary orbits, and Maestlin suggested that these spaces might be where comets frequently occur. This revelation was only possible under the assumption of a heliocentric universal organization. Maestlin is believed to have adopted the heliocentric view after observing the path of the Great Comet of 1577.When the comet appeared, Maestlin, along with the Danish astronomer Tycho Brahe, was one of the first to actively calculate its path in a more complex manner than simply tracking its movement across the sky. Tycho Brahe and Maestlin concluded that the comet was not just traveling across the sky but was also passing through Aristotle's and Ptolemy's solid geocentric orbs, suggesting that the planetary spheres were not solid, as previous astronomers had believed.
In 1589, Maestlin shared his conclusions about the comet's appearance with his friend, the astrologer Helisaeus Roeslin, who believed that the Great Comet of 1577 was located beyond the Moon.