The Institut de mécanique céleste et de calcul des éphémérides (Bureau des longitudes) offers to the public an information service which is accessible :

  by mail :
par e-mail :

Attention : The Institut de mécanique céleste does not receive the public

  • For any information which is not our competence (weather, stellar physics, astronomy out of the solar system, geographical coordinates...), visit the useful links page
  • For the Earth artificial satellites ephemeris, visit the DLR/GSOC.
  • For weather information, visit Météo-France.
  • For geographical coordinates, visitInstitut Géographique National.
  • To know the schedules of the tides, visit the SHOM (Service hydrographique et océanographique de la marine).
  • For the identification of objects rumored extraterrestrial (meteorids) contact theMuséum national d'histoire naturelle (MNHN). you can write to :

    Or send an E-mail to
    give your name, your adress (postal or e-mail), the right spot where you found the rock, why you think it's a meteorid, its size, its shape and its weight.
  • For a request about legal information (e.g exact hours of the sunrise or the sunset, illumination in a given place...), it is better to write us to :


    to obtain an official response.
  • For a request about the reproduction of our works, texts or images of this website, fill the form on the copyright page.
  • For a professional scientific request, identify your correspondent by consulting the pages of the scientific teams and send him a message.

Nota : The informations requiring specific calculations are invoiced. Please contact us.

Caution : This Website was created with the Ministère de l'Education Nationale, the CNRS and the CNES support. Any use of the data published on this website requires the IMCCE agreement..