The Astronomical Almanac is a joint publication of the U.S. Nautical Almanac Office, United States Naval Observatory (USNO) in the United States, Her Majesty's Nautical Almanac Office (HMNAO), and the United Kingdom Hydrographic Office (UKHO). This annual publication contains precise ephemerides of the Sun, Moon, planets, and satellites; data for eclipses and other astronomical phenomena for a given year; and serves as a worldwide standard for such information.