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Observatories > IMCCE

L'INSTITUT DE MECANIQUE CELESTE ET DE CALCUL DES EPHEMERIDES (IMCCE), former service des calculs du Bureau des longitudes (BDL), institute of Paris Observatory

Founded :  1795, 1961, 1998
Activities :  celestial mechanics, dynamical systems 
astrometry, planetology 
Information to general public :  by phone 33(1) 40 51 22 70 
from 10h to 12h and 14h to 16h 
access by Internet at and
Address :  77 avenue Denfert-Rochereau, F-75014 Paris
Phone :  33(1) 40 51 21 28


Crédit: JEA

IMCCE is located in this building of Paris Observatory since 1976.

Since 1998, the Institut de mécanique céleste et de calcul des éphémérides (IMCCE) and the Bureau des longitudes (BDL) are in charge of the official national french ephemerides.

The IMCCE, formerly known as Service des calculs du Bureau des longitudes, is in charge of the making of the ephemerides since 1961. Jean Kovalevsky was the first director (1961-1970) of the Service des Calculs followed by Bruno Morando (1971-1984), Jean Chapront (1985-1992), Jean-Eudes Arlot (1993-2002), William Thuillot (2003-2010) and Daniel Hestroffer (2011-2017). Jacques Laskar is now the director since 2017. This laboratory is made of 21 astronomers and researchers, 17 engineers and technicians and 15 PhD students. The laboratory is associated to the Centre National de la Recherche Scientifique (CNRS) since 1979 (UMR 8028).

The Bureau des longitudes is only an academy of 16 members and 32 correspondents (astronomers, geophysicists and physicists) working in their ownn laboratories or retired, proposing the offical missions of the IMCCE.

The IMCCE has three missions:
- the making of the ephemerides accessible through Internet or printed needed by the goverment, the navy and the civilian organisms;
- researches in celestial mechanics, astrometry and planetology and contributions to space missions;
- teaching to students (LMD) at Paris Observatory and in universities (UPMC, Lille University, Paris-Dauphine).

You will find here the history of Bureau des longitudes and Institut de mécanique céleste et de calcul des éphémérides and the official publications of IMCCE and BDL on its web site: