The Astronomical Almanac is the direct descendant of the British and
American navigational almanacs. The British Nautical Almanac and
Astronomical Ephemeris had been published since 1766, and was renamed
The Astronomical Ephemeris in 1960. The American Ephemeris and
Nautical Almanac had been published since 1852. In 1981 the British and
American publications were combined under the title The Astronomical
Almanac.
Chronology:
| 1766 | First edition of The Nautical Almanac and Astronomical Ephemeris, published by Astronomer Royal of England, with data for 1767. | |
| 1852 | First edition of The American Ephemeris and Nautical Almanac, with data for 1855. The US book publishes part of its data using the prime meridian of Washington, and part using the prime meridian of Greenwich. | |
| 1912 | U.S. Congress authorizes the international exchange of data. The official collaboration between the US and UK begins and continues today. | |
| 1941 | Almanacs adopt FK3 as the fundamental reference system | |
| 1960 | The title The Astronomical Ephemeris replaces, without loss of continuity of content, the previous UK title The Nautical Almanac and Astronomical Ephemeris. The Astronomical Ephemeris and the American Ephemeris and Nautical Almanac become identical in content. The U.S. and UK each produce about 50% of the text. | |
| 1961 | First edition of the Explanatory Supplement to the Astronomical Almanac is published. | |
| 1964 | Almanacs adopt FK4 as the fundamental reference system. | |
| 1968 | International Astronomical Union 1964 constants adopted. | |
| 1981 | Both almanacs change their name to The Astronomical Almanac. | |
| 1981 | Stars and Stellar Systems Section added. | |
| 1984 | International Astronomical Union 1976 constants and FK5 (J2000) system adopted. | |
| 1984 | Ephemeris Time (ET) replaced with Barycentric Dynamic Time (TDB) and Terrestrial Dynamical Time (TDT). | |
| 1984 | DE200/LE200 Jet Propulsion Laboratory planetary ephemerides adopted. | |
| 1992 | Second edition of the Explanatory Supplement to the Astronomical Almanac is published. | |
| 2003 | DE405/LE405 Jet Propulsion Laboratory planetary ephemerides adopted. Major revision of minor planet section. The Hipparcos Catalogue is the basis for the stellar data, replacing the FK5. | |
| 2006 | IAU/IERS "interim" precession and nutation models incorporated. | |
| 2009 | Finalized IAU precession and nutation models incorporated. |
