BornLyons, France, 21 June 1823
DiedSaint Jean en Royans, Drôme, France, 6 September 1873
Jean Chacornac was a dedicated observational astronomer. He began a career in commerce in Lyons and then Marseilles, where Jean Valz, director of the Marseilles Observatory, allowed him to use the telescopes. Chacornac studied sunspots and in 1852 discovered a comet (C/1852 K1). Thenceforth, he devoted himself fully to astronomy, assisting Valz in the discovery of minor planets and the essential precursor of ecliptic mapping.
Chacornac transferred to Paris as part of Urbain Le Verrier’s reform of the Paris Observatory in 1854, where most notably he published 36 maps of the ecliptic (1860–1863). Chacornac was renowned as a tireless worker and was highly thought of by scientists such as Jean-Bernard-Léon Foucault, but he was one of the numerous astronomers who in due course incurred Le Verrier’s displeasure.
In 1863, Chacornac retired to Villeurbanne, near Lyons, where he built a private...