Ernest Benjamin Esclangon (17 March 1876 – 28 January 1954) was a Frenchastronomer andmathematician.
Born inMison, Alpes-de-Haute-Provence, in 1895 he started to study mathematics at theÉcole Normale Supérieure, graduating in 1898. Looking for some means of financial support while he completed his doctorate onquasi-periodic functions, he took a post at theBordeaux Observatory, teaching some mathematics at theuniversity.
DuringWorld War I, he worked onballistics and developed a novel method for precisely locating enemy artillery. When a gun is fired, it initiates a sphericalshock wave but the projectile also generates a conical wave. By using the sound of distant guns to compare the two waves, Escaglon was able to make accurate predictions of gun locations.
After thearmistice in 1919,[1] Esclangon became director of theStrasbourg Observatory and professor of astronomy at theuniversity the following year. In 1929, he was appointed director of theParis Observatory and of theInternational Time Bureau, and elected to theBureau des Longitudes in 1932. He is perhaps best remembered for initiating in 1933 the firstspeaking clock service, reportedly to relieve the observatory staff from the numerous telephone calls requesting the exact time. He was elected to theAcadémie des Sciences in 1939.
Esclangon was the President of theSociété astronomique de France (SAF), the French astronomical society, from 1933–1935.[2] In 1935, he received thePrix Jules Janssen, the society's highest award.
Serving as director of the Paris Observatory throughoutWorld War II and theGerman occupation of Paris, he retired in 1944. He died inEyrenville, France.
Thebinary asteroid1509 Esclangona is named after him.
The lunar craterEsclangon is named after him.
His doctoral students includeDaniel Barbier,Édmée Chandon,Louis Couffignal,André-Louis Danjon, andNicolas Stoyko.[3]
