Minor Planet Circulars

Periodical publications

• Minor Planet Circulars (M.P.C. or MPCs), established 1947, is a scientific journal that is generally published by the Minor Planet Center on the date of each full moon, when the number of reported observations are minimal due to the brighter night sky. The Circulars contain astrometric observations, orbits and ephemerides of minor planets, comets and certain natural satellites. The astrometric observations of comets are published in full, while the minor planet observations are summarised by observatory code (the full observations now being given in the Minor Planet Circulars Supplement). New numberings and namings of minor planets (also see Naming of Minor Planets), as well as numberings of periodic comets and natural satellites, are announced in the Circulars. New orbits for comets and natural satellites appear in the Circulars; new orbits for minor planets appear in the Minor Planets and Comets Orbit Supplement (see below).
• The Minor Planet Electronic Circulars (MPECs) are published by the Minor Planet Center. They generally contain positional observations and orbits of unusual minor planets and all comets. Monthly lists of observable unusual objects, observable distant objects, observable comets and the critical list of numbered minor planets also appear on these circulars. Daily Orbit Update MPECs, issued every day, contain new identifications and orbits of minor planets, obtained over the previous 24 hours.
• The Minor Planets and Comets Supplement (MPS) is published on behalf of IAU's Division F (Planetary Systems and Bioastronomy) by the Minor Planet Center.
• The Minor Planets and Comets Orbit Supplement (MPO) is published on behalf of IAU's Division F by the Minor Planet Center.