Daniel Chalonge

Daniel Chalonge (January 21, 1895 – November 28, 1977) was a French astronomer and astrophysicist. He was born in Grenoble and studied in Paris under Charles Fabry.Chalonge worked as an astronomer at the Observatoire de Paris, the Observatoire d'Haute Provence and the Swiss Jungfraujoch Scientific Station. One of the founders of the Institut d'astrophysique de Paris, his studies included the stellar spectrum of hydrogen, stellar photometry and classification, and measurement of the ozone layer. Chalonge developed a microphotometer, which was subsequently named after him. Between 1936 and 1982 he authored (or co-authored) over 90 scientific papers.

Chalonge died in Paris.

• Janssen Medal from the French Academy of Sciences (1949)
• The crater Chalonge on the Moon is named after him.
• Chalonge mountain in the Alps is named after him.
• The International School of Astrophysics Daniel Chalonge is named after him.
• The Daniel Chalonge Museum in Erice, Italy is named after him.