The "Institut de Mécanique Céleste et de Calcul des Éphémérides" (IMCCE), Institute for Celestial Mechanics and Computation of Ephemerides, was created by decree of June 2, 1998 modifying that of the Paris Observatory and replacing the "Service de calcul et de mécanique céleste du Bureau des longitudes". This decree assigns to the IMCCE within the Observatory a mission of research and a mission of services particularly for the elaboration and dissemination of the ephemerides that it conducts under the auspices of the Bureau des longitudes. The IMCCE is also a joint-research Unit of the French CNRS (UMR 8028) integrated within PSL Research University and associated to the universities UPMC / Sorbonne Universités and University de Lille.


The IMCCE staff is composed of engineers or technicians, research scientists and university professors, lecturers, permanent or not. This staff depends on the Ministry of Education and Research (MENESR), or of the CNRS (Centre National de la Recherche Scientifique). Approximately forty people are on permanent position and, taking into account doctoral and post-doctoral candidates, the total staff of IMCCE is of the order of 65 people, to which are added trainees and visiting researchers staying in the Institute.

Research and Services

The IMCCE has two main activities: a research mission in celestial mechanics (see Research) in its mathematical as well as dynamical aspects, in astrometry and planetology; and a mission of service, especially for the development and dissemination of original ephemerides. IMCCE has also other national services (SNO - Service nationaux d'observation) defined by CNRS/INSU (see Services).

The research works of the Institute are carried out by three research teams:

  • Asteroids, Comets, Meteors and Ephemerides : ACME
  • Astronomy and Dynamic Systems : ASD
  • Planetology and Environments from Ground Astrometry and Space Exploration : PEGASE

These research teams work on different topics related to the dynamics and the solar (or planetary) system, and work together on large scientific projects.

IMCCE research has led to numerous publications in various international scientific journals, technical papers, PhD thesis, etc. The full list of these articles can be found here. A more complete description of the structure and activities of the IMCCE is given in the various activity reports published until 2004, and further in evaluation reports.

The IMCCE develops theories and several types of ephemerides for most of the objects in the Solar System, and disseminates these ephemerides by various means and supports.

  • Periodic (mostly yearly) works related to the missions of the Bureau of Longitudes. These works are:
    • Connaissance des Temps - Éphémérides astronomiques (since 1679, published by the Bureau des longitudes since 1795)
    • Annuaire du Bureau des longitudes - Guide de données astronomiques (since 1796)
    • Suppléments à la Connaissance des Temps relatifs aux satellites naturels (from 1978 to 2012)
    • Éphémérides nautiques (since 1889)
    • Éphémérides aéronautiques (from 1935 to 2012)
    • Encyclopédie Scientifique de l'Univers (1977)
    • Cahiers des sciences de l'Univers (1991)
  • Specific works related to the research and work of IMCCE staff:
    • Notes Scientifiques et Techniques de l'IMCCE.
    • Reference books.

You will find more information on these publications here.

In addition to the production of these publications, the IMCCE is an official French service that carries out specific astronomical calculations for different public or institutional users. These calculations are made under the solicitation of various administrative bodies such as the justice courts, insurance companies, architects, moviemakers or on behalf of scientific organizations such as astronomical observatories or space agencies.

An interactive real-time ephemerides server is available on the Internet for astronomers and general public who wish to obtain the positions of the solar system objects and their physical parameters (see the presentation page here). These ephemerides are moreover available through webservice protocol and through the Virtual Observatory center PADC.

The general public, amateur astronomers and associations also solicit the Institute which has developed an astronomical information service and proposes specific publications and data..

Space Activities

Beyond the tasks of calculating and publishing ephemerides of the solar system, the IMCCE has a strong involvement in space research, particularly in the field of space missions, as well for their preparation as for the analysis of their data.

Over the years, IMCCE intervened in the preparation of scientific missions such as Hipparcos, ISO, Rosetta, BepiColombo or Gaia. The IMCCE also provided scientific support throughout ISO missions and BeppoSAX, Gaia. The IMCCE's space research work has evolved with the growing needs of private and public space agencies and consortia. The researchers are particularly involved in projects of the CNES space agency, labex ESEP and space campuses, or ESA's cosmic vision program (JUICE, PLATO, CHEOPS, ...).

Its role in the fields of orbitography of space probes, its expertise in the implementation of reference systems, the theories of the movements of Solar System objects, as well as in the calculation of ephemerides, make the IMCCE a partner in the preparation of the European space missions of exploration of the Solar System. The Gaia and JUICE missions integrate the IMCCE ephemerides into their ground segment operations.

Teaching and Training

The IMCCE also has an educational and training activity:

  • Institutional researchers provide lessons as part of the cursus of Paris observatory, as well as in several universities and institutions (UPMC, Paris Diderot, Paris-Sud, Paris-Dauphine, ENS, univ. Lille, IPSA) on subjects related to the Institute's research themes (celestial mechanics, astrometry, dynamics, mathematics)
  • The institute welcomes, in addition to undergraduate PhD, students in the bachelor's and master's degrees, as well as student-engineers in internships and training periods from 2 to 6 months, supervised by IMCCE researchers
  • Seminars and conferences for various audiences are also offered by and at the IMCCE.

Last update Tuesday 12 December 2017