The Minor Planet Circulars (MPCs) is a scientific journal that is generally published on the date of each full moon by the Minor Planet Center. 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, as well as numberings of periodic comets, 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.