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Louis Thollon (May 2, 1829 – April 8, 1887) was a French astronomer.

He was born in Ambronay, France.[1] Beginning in 1881, Thollon joined the staff of the new Nice Observatory where he undertook a long-term observation program of the Sun using a spectroscope of his own design.[2] In the process, he recorded a solar spectrum consisting of 3,000 absorption lines in the optical band.[3]

In 1882, he joined André Puiseux on an expedition to Egypt to observe the solar eclipse on May 17.[4] The same year he traveled to Portugal to watch the Venus transit, but met with disappointment.[5] During the 1886 Mars opposition, he assisted the observatory director, Henri Perrotin, in observing the planet with a 15 in (38 cm) reflecting telescope. Both men reported that they spotted canali on the surface of the planet, apparently confirming the 1877 discovery of these features by Italian astronomer Giovanni Schiaparelli.[6] Thollon died in Lyon, France.[1]


  1. ^ a b Wolf, Rudolf (1890), Handbuch der Astronomie: ihrer Geschichte und Litteratur, 1, F. Schulthess, p. 504
  2. ^ Hutchins, Roger (2008), British university observatories, 1772-1939, Ashgate Publishing, Ltd., p. 252, ISBN 0-7546-3250-4
  3. ^ Launay, Françoise (2011), The Astronomer Jules Janssen: A Globetrotter of Celestial Physics, Astrophysics and Space Science Library, 380, Springer, p. 183, ISBN 1-4614-0696-X
  4. ^ "Progress in astronomy in 1882", The English Mechanic, January 5, 1883
  5. ^ "Notes", The Observatory, 6 (69): 25
  6. ^ Leverington, David (2003), Babylon to Voyager and beyond: a history of planetary astronomy, Cambridge University Press, p. 239, ISBN 0-521-80840-5