Félix Tisserand

François Félix Tisserand (13 January 1845 – 20 October 1896) was a French astronomer. Tisserand was born at Nuits-Saint-Georges, Côte-d'Or. In 1863 he entered the École Normale Supérieure, and on leaving he went for a month as professor at the lycée at Metz. Urbain Le Verrier offered him a post in the Paris Observatory, which he entered as astronome adjoint in September 1866. In 1868 he took his doctor's degree with a thesis on Delaunay's Method, which he showed to be of much wider scope than had been contemplated by its inventor. Shortly afterwards he went out to Kra Isthmus with Édouard Stephan and Georges Rayet to observe the 1868 solar eclipse. The French astronomers were accompanied by Mongkut, the King of Siam who had calculated the location and the date of the eclipse by himself two years before and prepared a comfortable watching place for the scientists. In 1873 he was appointed director of the observatory at Toulouse, where he published his Recueil d'exercices sur le calcul infinitesimal, and in 1874 became corresponding member of the Académie des Sciences. He took part in the French expeditions of 1874, accompanied by Jules Janssen, to Japan, and in 1882, accompanied by Guillaume Bigourdan, to Martinique to observe the transits of Venus. In 1878 he was elected a member of the Académie des Sciences in succession to Le Verrier, and became a member of the Bureau des Longitudes. In the same year he was appointed professeur suppliant to Liouville, and in 1883 he succeeded Puiseux in the chair of celestial mechanics at the Sorbonne. Tisserand always found time to continue his important researches in mathematical astronomy, and the pages of the Comptes rendus bear witness to his activity. His writings relate to almost every branch of celestial mechanics, and are always distinguished by rigour and simplicity in the solution of the most difficult problems.