Christoph Rothmann

Signature of Christoph Rothmann

Christoph Rothmann (* between 1550 and 1560 in Bernburg ; †  1601 in Bernburg) was a German mathematician and one of the few known astronomers of his time, but was forgotten in the course of the 17th century. His research contributed significantly to the fact that Kassel became a European center of astronomy in the 16th century.

Life

To this day it is not known when Rothmann was born, but his place of birth in Bernburg an der Saale is known. It is estimated that it must have been between 1550 and 1560. His social and family origins are also unknown. After schooling at home, he studied theology and mathematics at the University of Wittenberg with the support of Prince Joachim Ernst von Anhalt . Rothmann's enthusiasm for astronomy was expressed, as he later confessed in a letter to Tycho Brahe . The exact date of his matriculation at the University of Wittenberg on August 1, 1575 as Christophorus Rothmannus Bernburgensis is documented .

On June 2, 1582, Rothmann enrolled as "M. Christophorus Rothmannus Bernburgensis" at the Illustre grammar school in Zerbst in Anhalt, which opened on January 30, 1582 . He followed his brother, who had already enrolled in Zerbst a few days earlier, on May 14, 1582. Both brothers are listed in the Zerbst registry as princely scholarship holders (presumably from Prince Joachim Ernst von Anhalt ).

From 1584 to 1590, Christoph Rothmann worked at the astronomical enthusiast Landgrave Wilhelm IV of Hessen-Kassel . The exact date of his entry into the Landgrave's service is not known, but can be easily traced based on known correspondence. According to this, Rothmann must have arrived in Kassel on November 15, 1584. His research contributed significantly to the fact that Kassel became a center of celestial research.

In May 1590 Rothmann began a trip to Uraniborg to see Tycho Brahe , who received him in Copenhagen. They arrived on August 1, 1590 on the island of Hven , where Rothmann stayed until September 1, 1590 and then left again. In breach of all obligations and customs, Rothmann did not return to Kassel, but went to his hometown of Bernburg. This not only ended his employment at the Kasseler Hof, but also meant an abrupt end to his famous work on the Kassel star catalog . The reasons are not known, although there is an extensive correspondence between Tycho Brahe and the Landgrave on the one hand, and, after Rothmann's silence for four years, on the other hand, to Tycho. In a 21-page letter to Rothmann, Tycho tried to persuade the former Kassel astronomer to return, but unsuccessfully. Apparently it was only in 1597 that Rothmann offered his services to the new Landgrave Moritz, son of Wilhelm IV, to finish work on the star catalog. Moritz 'answer is not known, but he refused for understandable reasons.

Christoph Rothmann lived in Bernburg until his death in the summer of 1601, where he wrote a few less well-known theological writings that were irrelevant.

Christoph Rothmann had at least one brother, Johannes, who had stayed in Kassel several times, including in January 1586 and 1587, and took part in observations. Like his brother, Johannes Rothmann had studied in Wittenberg since 1578.

The Kassel star catalog

Landgrave Wilhelm IV endeavored from the beginning to give astronomical observations of the sky a reliable empirical basis. His main interest was the precise determination of the position of the fixed stars and their mutual distances. They were the foundation of then (and now) astronomy and especially as reference points for measuring planetary motion.

Christoph Rothmann calculated and carried out the Kassel star catalog , a list of 387 star words , almost alone between 1585 and 1587, albeit with the expert assistance of the Landgrave. He did not work with instruments of huge dimensions like Tycho Brahe, but used medium-sized metal instruments with precise sighting devices, for example the azimuthal quadrant or a sextant . Rothmann was relatively more by the handy size of the instruments aimings reach than it would have been with larger instruments at that time possible. He also paid great attention to precise clocks, which were designed by Jost Bürgi in Kassel, who also worked for the Landgrave . In addition, Rothmann took into account the astronomical refraction and observed each fixed star several times (see Rothmann's writing: Observatorium stellarum liber primus ). He achieved an accuracy of about 1.5 '(1/20 moon diameter), ten times better than the data previously used by Claudius Ptolemy and practically as good as the measurements by Tycho.

Wilhelm IV received daily reports from Rothmann, who was a staunch supporter of Nicolaus Copernicus and his heliocentric worldview .

meaning

In the 16th century, two groups of researchers in Europe had distinguished themselves by setting up new, more precise star catalogs. On the one hand the well-known Dane Tycho Brahe, who built the famous Uranienburg observatory on the island of Ven, and an observation group in Kassel at the court of the landgrave. Rothmann and Jost Bürgi , a Swiss mathematician and watchmaker, worked here. The two working groups cultivated a lively scientific exchange, as evidenced by an extensive exchange of letters between Kassel and Ven, and an unconditional recognition of the other's achievements. The star observations of these two groups were the most accurate that had been achieved with the exclusive use of the sighting principle via the rear sight and front sight until finally in 1610 the invention of the telescope revolutionized astronomy from the ground up.

A letter between Rothmann and Brahe, which was often quoted later, became known, which showed the whole dilemma of physics at the time. Brahe, who mistrusted the heliocentric worldview of Nicolaus Copernicus, raised the following objection to the movement of the earth in a letter to Rothmann: “If the earth actually rotates from west to east, then a cannonball that is shot in the direction of the earth's rotation must fly much further than a projectile fired in the opposite direction. ” Rothmann replied that both the projectile and the cannon participate in the earth's movement and that his objection was therefore invalid. However, this contradicted the Aristotelian view of movement that was valid in Europe at the time . The contradiction that was so fundamental at the time could only be eliminated in the middle of the 17th century with the discovery of gravity .

In contrast to his prominent astronomical colleagues, Rothmann was forgotten in the 17th century.

The crater Rothmann (42 km in diameter) was named after Christoph Rothmann .

Fonts

• Astronomia: In qua hypotheses Ptolemaicae ex hypothesibus Copernici corriguntur et supplentur: et imprimis intellectus et usus tabularum Prutenicarum declaratur et demonstratur , manuscripts from 1580, (in the Kassel University Library)
• Observatorium stellarum liber primus , Kassel 1589 (Handbuch der Astronomie, a compendium of theoretical and practical astronomy of the late 16th century, and Christoph Rothmann's best-known book)
• Restitutio Sacramentorum , Goslar 1611, (posthumously published theological text)
• Scriptum de cometa, qui anni Christi 1585 mensib. Octobri and Novembri apparuit. Published by Willebrord Snellius in: Descriptio cometae, qui anno 1618 mense Novembri primum effulsit (pages 69–156), Verlag Elzevir, Leiden 1619

literature

• Christoph Rothmann, Miguel A. Granada, Jürgen Hamel , Ludolf von Mackensen: Christoph Rothmanns Handbuch der Astronomie from 1589 . Verlag Harri Deutsch 2003, ISBN 978-3-8171-1718-5
• Miguel A. Granada: Christoph Rothmann and the dissolution of the heavenly spheres . The letters to the Landgrave of Hessen-Kassel 1585. In contributions to the history of astronomy, Volume 2 , edited by Wolfgang R. Dick and Jürgen Hamel , Frankfurt am Main 1999, pp. 34–57 [1]
• Nils Lenke, Nicolas Roudet: Johannes, Christoph and Bartholomaeus Rothmann. Some biographical additions to the Rothmann brothers . In Acta historica Astronomiae , Vol. 52, Leipzig 2014, pp. 223–242.
• Walther Killy : Literature Lexicon. Authors and works in German (15 volumes). Gütersloh, Munich: Bertelsmann-Lexikon-Verl., 1988–1991 (CD-ROM: Berlin 1998, ISBN 3-932544-13-7 )
• Siegmund Günther:  Rothmann, Christoph . In: Allgemeine Deutsche Biographie (ADB). Volume 29, Duncker & Humblot, Leipzig 1889, pp. 370-372.
• Andreas Kühne:  Rothmann, Christoph. In: New German Biography (NDB). Volume 22, Duncker & Humblot, Berlin 2005, ISBN 3-428-11203-2 , p. 127 f. ( Digitized version ).

Web links

• Literature by and about Christoph Rothmann in the catalog of the German National Library

Individual evidence

1. ↑ Nils Lenke, Nicolas Roudet: John Christopher and Bartholomew Rothmann. Some biographical additions to the Rothmann brothers . In Acta historica Astronomiae , Vol. 52, Leipzig 2014, p. 239
2. ^ Rothmann's letter to Tycho Brahe dated September 21, 1587, published in Emil Dreyer: Tychonis Brahe Dani Opera omnia VI, Copenhagen 1919
3. ^ Album Academiae Vitebergensis , older series: 1502–1602, edited by Otto Hartwig Halle an der Saale 1894 (re-edition Aalen 1976), page 255
4. ^ Specht, Reinhold: The register of the Illustre high school in Zerbst in Anhalt 1582–1797, Leipzig 1930
5. ^ Castan, Joachim: Higher education and reformed denominationalization - The Illustre high school of the Principality of Anhalt in Zerbst 1582–1652, Halle (Saale) 1999
6. ↑ Christoph Rothmanns Handbuch der Astronomie from 1589 , Christoph Rothmann, Miguel A. Granada, Jürgen Hamel, Ludolf von Mackensen , Verlag Harri Deutsch 2003
7. ^ Tycho's letter to Wilhelm IV of April 1, 1591, published in Emil Dreyer: Tychonis Brahe Dani Opera omnia IX, Copenhagen 1927
8. ^ Rothmann's letter to Tycho Brahe of January 14, 1595, published in Emil Dreyer: Tychonis Brahe Dani Opera omnia VI, Copenhagen 1919
9. ^ Rothmann's letter to Landgrave Moritz dated March 29, 1597, published in Emil Dreyer: Tychonis Brahe Dani Opera omnia VI, Copenhagen 1919
10. ^ Christoph Rothmann: Letter to Wilhelm IV of January 8, 1586, Hessisches Staatsarchiv Marburg
11. ↑ Jürgen Hamel: History of Astronomy in Source Texts . Spektrum Akad. Verlag, Heidelberg 1996, ISBN 3-8274-0072-4 , pp. 37 .
12. ↑ Original from the Herzog August Library Wolfenbüttel ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.