Ernest Benjamin Esclangon (17 March 1876 – 28 January 1954) was a French astronomer and mathematician. Born in Mison, Alpes-de-Haute-Provence, in 1895 he started to study mathematics at the École Normale Supérieure, graduating in 1898. Looking for some means of financial support while he completed his doctorate on

quasi-periodic function In mathematics, a quasiperiodic function is a function (mathematics), function that has a certain similarity to a periodic function. A function f is quasiperiodic with quasiperiod \omega if f(z + \omega) = g(z,f(z)), where g is a "''simpler''" fu ...

s, he took a post at the

Bordeaux Observatory The Bordeaux Observatory is an astronomical observatory affiliated with the University of Bordeaux. Built in Floirac, France in 1893 its lenses were focused between +11 and +17 degrees declination. Until 1970 it had taken over 4,000 photographi ...

, teaching some mathematics at the university. During World War I, he worked on

ballistics Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially ranged weapon munitions such as bullets, unguided bombs, rockets or the like; the science or art of designing and a ...

and developed a novel method for precisely locating enemy artillery. When a gun is fired, it initiates a spherical shock 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 the armistice in 1919, Esclangon became director of the

Strasbourg Observatory The Observatory of Strasbourg is an astronomical observatory in Strasbourg, France. Following the Franco-Prussian War of 1870–71, the city of Strasbourg became part of the German Empire. The University of Strasbourg was refounded in 1872 an ...

and professor of astronomy at the university the following year. In 1929, he was appointed director of the

Paris Observatory The Paris Observatory (french: Observatoire de Paris ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its histor ...

and of the International Time Bureau, and elected to the

Bureau des Longitudes Bureau ( ) may refer to: Agencies and organizations *Government agency *Public administration * News bureau, an office for gathering or distributing news, generally for a given geographical location * Bureau (European Parliament), the administrat ...

in 1932. He is perhaps best remembered for initiating in 1933 the first '' speaking clock'' service, reportedly to relieve the observatory staff from the numerous telephone calls requesting the exact time. He was elected to the Académie des Sciences in 1939. Esclangon was the President of the Société astronomique de France (SAF), the French astronomical society, from 1933–1935.de la Société astronomique de France'', November 1937, plates X–IX
/ref> In 1935, he received the

Prix Jules Janssen The Prix Jules Janssen is the highest award of the Société astronomique de France (SAF), the French astronomical society. This annual prize is given to a professional French astronomer or to an astronomer of another nationality in recognition ...

, the society's highest award. Serving as director of the Paris Observatory throughout World War II and the German occupation of Paris, he retired in 1944. He died in Eyrenville, France. The binary asteroid

1509 Esclangona 1509 Esclangona, provisional designation , is a rare-type Hungaria asteroid and binary system from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It is named after French astronomer Ernest Esclangon. Discoveries ...

is named after him. The lunar crater Esclangon is named after him.

References

External links

* {{DEFAULTSORT:Esclangon, Ernest 20th-century French astronomers 1876 births 1954 deaths Members of the French Academy of Sciences École Normale Supérieure alumni Academic staff of the University of Strasbourg People from Alpes-de-Haute-Provence 20th-century French mathematicians Presidents of the International Astronomical Union