• MPC Preparation (Info)
  • The Minor Planet Center (MPC) operates at the Smithsonian Astrophysical Observatory (SAO), under the auspices of Division F (formerly Division III and, before that, Commission 20) of the International Astronomical Union (IAU). The Minor Planet Center derives its operating budget from a five-year NASA grant.

    The MPC is responsible for the designation of minor bodies in the solar system: minor planets; comets; and natural satellites. The MPC is also responsible for the efficient collection, computation, checking and dissemination of astrometric observations and orbits for minor planets and comets, via its various journals:

    • Minor Planet Circulars (issued generally on a monthly basis)
    • Minor Planet Circulars Orbit Supplement (MPO) (issued up to thirteen times per year)
    • Minor Planet Circulars Supplement (MPS) (issued three or four times a month)
    • Minor Planet Electronic Circulars (MPECs) (issued as necessary, generally at least once per day)

    MPC Publications and Services

    Services for Observers

    Large Data Sets

    Access the large observation and orbit data files generated by the MPC.
    • MPCAT: Complete (and update) orbit files
    • MPCAT-OBS: Observation files
    • MPCUPDATE: Files associated with MPC batches
    • MPCArchive: PDF versions of the MPC's various journals.
    • Data sets: Links to text and JSON versions of various data files. [Added 2016 Apr. 21]


    • Documentation about the various aspects of the MPC's operations.

    Lists and plots