Bernhard Walther

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Walther's house in which the observatory was located. Today the Albrecht Dürer House

Bernhard Walther (* 1430 in Memmingen ; † June 19, 1504 in Nuremberg ) was an astronomer , humanist and businessman. The student, patron and successor of Regiomontanus , a citizen of Nuremberg since 1467, is considered the most precise astronomical observer of his time.

Life

Walther was initially a factor in the Memminger Vöhlin Society in Nuremberg and as such was very successful and given special powers. He played a notable role in Nuremberg. As a patron and sponsor of the Regiomontanus, he made it possible for it to build the first observatory in Germany. Later he had relationships with Albert Dürer , and perhaps also with Veit Stoss, whose characters Adam and Eve probably came to the Lisbon court through the Welser-Vöhlin Society. In 1501 he was accepted into the larger council of the city of Nuremberg. His marriage to Christiane Amman (? -1498) remained childless and the heirs squandered his library and instruments. His house was acquired by Albrecht Dürer in 1509 and is now a museum .

Contribution to astronomy

Walther made it possible for Regiomontanus to set up an observatory and printer's workshop in Nuremberg in 1471 , which he continued after his death in 1476. He acquired the library and the astronomical instruments of his teacher and friend after Hans von Dorn had negotiated in vain with the city council of Nuremberg on behalf of the Hungarian king. In particular, he continued the systematic observations of the planets begun by Regiomontanus with an astrolabe (measuring armillary sphere ) over 30 years until his death. The observation time was usually determined classically using star heights. But he was also the first to use a (rather imprecise) wheel clock. The clocks of that time did not yet have a minute hand, so he read the minutes from the position of the gears. He was the first astronomer to take into account the refraction of light in the earth's atmosphere. These are the first "modern" series of observations. Regiomontanus intended to be able to set up better planet tables in order to obtain more precise data for the creation of horoscopes. In total, they determined 746 sun heights to determine the year points and the year length. In addition, they measured 615 planetary positions with longitude and latitude. Unfortunately, around 1500 nobody could be found who systematically compared these measurements with the traditional planet tables. It was not until Tycho Brahe took up the systematic observations again, whereby he partially deliberately leaned on measurements by Walther in order to be able to find possible changes in the orbit parameters over time.

Nicolaus Copernicus used the observations of Mercury, but ascribed them to Schöner, who had communicated them to him before publication. There were 45 observations, 14 of which were longitude and latitude. In Copernicus' main work three observations of Mercury are given, but only the lengths. But they do not agree with the values ​​published in 1544. In 1618 they were reissued by Willebrord Snell as an appendix to Coeli et siderum in eo errantium observaciones hassiacae .

Walthers and Regiomontanus measurements were not published until 1544 by his student Johannes Schöner (1477–1547): Observationes XXX annorum a I. Regiomontano et B. Walthero Norimbergae habitae .

meteorology

At that time, weather forecasts were also derived from horoscopes. Regiomontanus and Walther also recorded meteorological observations to check the forecasts. Walther's treatise Canones de judiciis aurae was published by his astrological student Johannes Schöner .

Timing

Also and especially through his astronomical work he gained a high reputation in Nuremberg. The council commissioned him to calculate the course of the day lengths, which were taken as the basis for the reform of the so-called Nuremberg clock in 1489 . A change in its dates was only necessary in 1700 with the introduction of the Improved Imperial Calendar (commonly known as the Gregorian calendar ) in the Protestant countries of Germany. The sundial installed in 1502 on the east choir of the Lorenzkirche , which shows the Nuremberg hours, was calculated by Johannes Stabius with the help of works by Walther. Walther had translated Apollonius von Perga's doctrine of conic sections from Greek into Latin and wrote a treatise on the manufacture of sundials with the help of conic sections. Both works are lost.

Honors

Johannes Hevelius honors him by placing him on the frontispiece of his sky atlas Firmamentum Sobiescianum in a row with astronomers such as Tycho Brahe , Hipparchus , Ptolemy and Copernicus . The crater Walther on the earth's moon bears his name.

Works (selection)

  • Johannes Regiomontanus: Opera Collectanea . Otto Zeller, Osnabrück 1972 (contains the traditional observations of Bernhard Walther)

Literature (selection)

  • Raimund Eirich: Bernhard Walther (1430–1504) and his family . In: Mitteilungen des Verein für Geschichte der Stadt Nürnberg 74 (1987), pp. 77–128
  • Hans Gaab: A contemporary of Martin Behaim: The merchant Bernhard Walther (1430–1504), astronomer and previous owner of the Albrecht Dürer House . Norica 3 (July 2007), pp. 69-77
  • Richard L. Kremer: Bernhard Walther's Astronomical Observations . In: Journal for the History of Astronomy 11 (3/1980) pp. 174-191
  • Richard L. Kremer: The Use of Bernhard Walther's Astronomical Observations: Theory and Observation in Early Modern Astronomy . In: Journal for the History of Astronomy 12 (2/1981), pp. 124-132
  • Robert R. Newton: An analysis of the solar observations of Regiomontanus and Walther . In: Quarterly Journal of the Royal Astronomical Society 23 (1982), pp. 67-93
  • Richard L. Kremer: Walther's Solar Observations: A reply to RR Newton . In: Quarterly Journal of the Royal Astronomical Society 24 (1983), pp. 36-47
  • Kurt Pilz: Bernhard Walther and his astronomical observation stands . In: Mitteilungen des Verein für Geschichte der Stadt Nürnberg 57 (1970), pp. 176–188
  • John Michael Steele, Francis Richard Stephenson: Eclipse Observations by Regiomontanus and Walther . In: Journal for the history of astronomy 29 (4/1998), pp. 331-344
  • Ernst Zinner: Life and work of Joh. Müller von Königsberg called Regiomontanus . 2. verb. Edition Otto Zeller, Osnabrück 1968
  • Johann Christian Poggendorff : Biographical-literary concise dictionary of the exact natural sciences.
  • Ernst Zinner: Origin and Spread of the Coppernican Teaching. 2nd edition Munich 1988, ISBN 3-406-32049-X
  • Hans Gaab: The great Nuremberg clock. In: Contributions to the history of astronomy. 8 (2006) pp. 43-90; Acta Historica Astronomiae, Vol. 28, ISBN 3-8171-1771-X
  • Siegmund Günther :  Walther, Bernhard . In: Allgemeine Deutsche Biographie (ADB). Volume 41, Duncker & Humblot, Leipzig 1896, pp. 97-99.
  • Walther, Bernhard, an astronomus. In: Johann Heinrich Zedler : Large complete universal lexicon of all sciences and arts . Volume 52, Leipzig 1747, column 1829-1831.

Web links

Individual evidence

  1. ↑ Ralf Kern: Scientific instruments in their time . Volume 1: From astrolabe to mathematical cutlery . Cologne, 2010. p. 112.
  2. ↑ 4 °, Lugd. Bat. 1618
  3. ^ 4 °, Norimb. 1544
personal data
SURNAME Walther, Bernhard
BRIEF DESCRIPTION Nuremberg astronomer of the Middle Ages, patron of Regiomontanus
DATE OF BIRTH 1430
PLACE OF BIRTH Memmingen
DATE OF DEATH June 19, 1504
Place of death Nuremberg