History of The Astronomical Almanac
Astronomical Applications Dept. Astronomical Applications Dept.
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Picture of the 2013 Astronomical Almanac 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.

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.
1900 First edition based on Newcomb and Hill's planetary ephemerides and other research being performed in the office since 1877.
1912 U.S. Congress authorizes the international exchange of data. The official collaboration between the US and UK begins and continues today.
1916 International cooperation commenced with this volume.
1925 Civil time introduced with notation GCT. Day change to begin at midnight instead of noon.
1941 Almanacs adopt FK3 as the fundamental reference system
1953 Use of term GCT eliminated from this issue. It was first introduced in the 1925 edition.
1955 Agreed with the British Nautical Almanac Office that, beginning with the volume for 1960, the contents of the American Ephemeris and the British Nautical Almanac will be identical. Half of the production will be done in the U.S. and half in England, and the printing will be done independently in the two countries. The unified volume is used in Germany in place of the former Berliner Jahrbuch (which has been discontinued); and parts of the volume are reproduced in the Japanese Ephemeris.
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 US and UK each produce about 50% of the work.
1961 First edition of the Explanatory Supplement to the Astronomical Almanac is published. Explains the derivation and contents of the annual book.
1964 Almanacs adopt FK4 as the fundamental reference system.
1968 In accordance with the recommendations of the 12th General Assembly of the International Astronomical Union (IAU), the IAU 1964 constants were adopted beginning with this volume.
1968 With the edition for 1968, there was included a "Supplement to the A.E. 1968" containing the exposition of the IAU System of Astronomical Constants. Reprints of this Supplement were printed.
1972 With the edition for 1972, additional precision was given for: tabulated longitude of the Sun, half day values of the horizontal parallax of the Moon, and tabulated true distance of the planets from Earth. Minor planets ephemerides were given throughout the year. A new section, the Moon's distance in units of Earth's equatorial radius, was added.
1974 With the edition for 1974, preliminary pages were re-organized and notes on the visibility of the planets were added. The physical ephemerides of Mars and Saturn were extended to cover the entire year.
1981 The 1981 edition was reformatted, the named changed to The Astronomical Almanac and a single printing performed in the US for shipment to England. The division of labor was completely redefined.
1981 Stars and Stellar Systems Section added.
1982 With the edition for 1982, data for sigma Octantus was introduced in addition to Polaris. A method of providing precise latitude and azimuth in the Southern Hemisphere, and a formula for Pole star was added. A table of geocentric rectangular coordinates of the Sun was included.
1984 With the edition for 1984, the International Astronomical Union 1976 constants and FK5 (J2000) system was adopted. Ephemeris Time (ET) was replaced with Barycentric Dynamic Time (TDB) and Terrestrial Dynamical Time (TDT). The basis for the ephemerides was changed to Jet Propulsion Laboratory's DE200/LE200.
1984 The edition for 1984 included a Supplement to the Astronomical Almanac 1984, which detailed the introduction of the improved IAU System of Astronomical Constants, Time Scales and Reference Frame into The Astronomical Almanac.
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.
2011 The edition for the 2011 included a list of exoplanets and host stars. Lunar librations are derived from JPL's LE403 lunar rotation ephemeris.
2012 The edition for the 2012 introduced Minor Planet Center (MPC) codes in the Observatory List.
2012 Third edition of the Explanatory Supplement to the Astronomical Almanac is published.
2013 Pluto data reorganized and added to newly named Section G, Dwarf Planets & Small Solar System Bodies.
2015 Jet Propulsion Laboratory's DE430/LE430 planetary ephemerides was adopted. The IAU 2012 resolution on the re-definition of the astronomical unit of length was implemented. Predicting magnitude and surface brightness of planets was updated to account for the geometry of oblate planets.
2016 The basis for Ceres ephemeris is now Jet Propulsion Laboratory's Horizons data.