The Bureau des longitudes was founded by a law of the Convention Nationale (French national assembly) on June 25, 1795 (7 messidor year III of the republican calendar). The main goals were to solve the astronomical problems involved in the determination of longitude at sea, strategic at that time (its name comes from this activity), to calculate and publish the ephemerides (la Connaissance des Temps) and an almanac suitable to regulate those of the Republic ”, to organize scientific expeditions in the geophysical and astronomical fields and to be a consultative committee for some scientific problems. The Observatoire de Paris was under its direction until 1854.
Since its foundation, the structure and the activities of the Bureau des longitudes changed considerably. The initial structure was a committee of ten scientists : Lagrange, Laplace, Méchain, Lalande, Cassini, Delambre, Borda, Bougainville, Buache et Caroché. Five other members were associated for calculations. In 1802 the Service of Calculations was founded and was in charge of the ephemerides computation.
The structure of this service was reshaped several times and in 1961, A. Danjon and J Kovalevsky created a modern research laboratory, replacing the old service des calculs, which became the Service des Calculs et de Mécanique Céleste du Bureau des longitudes. Besides its missions of ephemerides computation, an intense research activity was developed in the dynamical and celestial mechanic fields. In 1979 it was associated to the Centre National de la Recherche Scientifique. In 1998, it becomes the Institut de mécanique céleste et de calcul des éphémérides (IMCCE) within the theObservatoire de Paris.
The bicentenary of the Bureau des longitudes was celebrated in Paris on July 3, 1995. (symposium 172).
Since 1998, two entities contribute to the development of the national ephemerides: Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE) and the Bureau des Longitudes.