Carl Braun (astronomer)

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Carl Braun SJ , also Karl Braun , (born April 27, 1831 in Neustadt (Hesse) , † June 3, 1907 in Sankt Radegund near Graz ) was a German Jesuit and astronomer .


Carl Braun attended the Germanicum in Rome and studied at the Pontifical Gregorian University , where, among other things, he attended lectures on astronomy with Angelo Secchi . After seven years of study, he received his doctorate in philosophy and theology. He then became a professor at the seminary in Fulda and joined the Society of Jesus in 1861 , which entrusted him with teaching physics to the students of the order. Braun attended lectures in mathematics in Paris for a year and worked another year as a tutor at the Gregoriana, where he came into closer contact with Angelo Secchi.

In 1871 he withdrew into private life, presumably because of his increasing hearing loss. In 1878 he was appointed the first director of the newly built Haynald Observatory in Kalocsa , Hungary, and spent the following years building the observatory. In 1884 he applied for removal from his position and withdrew to Mariaschein in Bohemia, where he devoted himself to private research. He died in 1907 in St. Radegund near Graz, where he regularly spent the summer months to relax.


As the first director of the Brown built Haynald Observatory and let a Merz - refractor with 18 cm aperture and an equatorial mount and a Hilger- spectroscope purchase for studying the sun. With the latter he observed sunspots , prominences and sun flares .

Braun was a resourceful inventor of technical devices, many of which, however, were not realized and ignored. He designed various physical, mathematical and meteorological devices and even an explosive projectile for the artillery and a mitrailleuse .

He constructed a nephoscope , an instrument for measuring the direction and apparent speed of cloud movements and thus the wind in higher regions.

In 1867 he developed the impersonal micrometer for meridian observations of right ascensions , which was redesigned in a simpler form in 1889 by Johann Adolf Repsold .

In 1873 he invented an apparatus for photography of the entire solar disk in monochromatic light , as it was later developed by George Ellery Hale and Henri-Alexandre Deslandres on the same principle.

Braun determined the gravitational constant with a rotary balance in a vacuum with a high level of accuracy for the time. The result of his ten years of work was published in 1897.

The Jesuit also dealt with cosmological questions and their relation to the Christian faith.

Publications (selection)


  • The passage micrometer: Apparatus for the more precise determination of the time of star passages, the rectascensions of the stars and the geographical longitude. The Nephoscope: Instrument for determining the direction and speed of the wind in higher regions, together with an appendix about some military inventions. Otto Wigand, Leipzig 1865
  • Reports from the Archbishop's Haynald Observatory at Kalocsa in Hungary on the work carried out there in the first five years. Aschendorff, Münster i. W. 1886
  • On cosmogony from the standpoint of Christian science: together with a theory of the sun and some related philosophical considerations. Aschendorff, Münster i. W. 1905

In magazines

  • By direct photography of the solar protuberances. In: Astronomische Nachrichten, 80 (1872), 33–42 ( digitized version )
  • About an application of dragonflies to the determination of the division error of a circle. In: Astronomische Nachrichten, 102 (1882), 375–376 ( digitized version )
  • Observation of the solar eclipse of 1882 May 16 on the Archbishop. Haynald Observatory in Kalocsa. In: Astronomische Nachrichten, 102 (1882), 377–378 ( digitized version )
  • About cosmic dust and the moon acceleration. In: Astronomische Nachrichten, 108 (1884), 259–262 ( digitized version )
  • Observations of the Comet 1884 I (Pons 1812). In: Astronomische Nachrichten, 109 (1884), 61–64 ( digitized version )
  • About photographic recordings of the solar prominences. In: Astronomische Nachrichten, 126 (1891), 227–228 ( digitized version )
  • The gravitational constant, the mass and mean density of the earth. According to a new experimental determination. In: Memoranda of the Imperial Academy of Sciences, Mathematisch-Naturwissenschaftliche Classe, Volume 64 (1897), 187-258 ( digitized version )


Individual evidence

  1. Augustín Udías: Searching the Heavens and the Earth: The History of Jesuit Observatories. Astrophysics and Space Science Library 286, Springer, Dordrecht 2003, ISBN 978-90-481-6252-9 , doi : 10.1007 / 978-94-017-0349-9 , pp. 74-75