The Astronomical Almanac


AsA 2006 Cover

The Astronomical Almanac contains a wide variety of both technical and general astronomical information. The book is a worldwide resource for fundamental astronomical data. It is a joint publication of the U.S. Nautical Almanac Office and Her Majesty's Nautical Almanac Office in the United Kingdom, and contains data supplied by many scientists from around the world. The online companion, The Astronomical Almanac Online, extends the printed version by providing data best presented in machine-readable form.

The material appears in sections, each section addressing a specific astronomical category. The book also includes references to the material, explanations, and examples. It is available one year in advance of its date. Parts of Sections A and B are available two years in advance in Astronomical Phenomena.


Online Companion

The Astronomical Almanac Online pages are available at USNO and HMNAO. Online data are provided for several years. The latest update to The Astronomical Almanac Online provides data that accompanies the 2018 edition of The Astronomical Almanac. The site includes sections on Besselian and second-order day numbers, lunar polynomial coefficients, satellite offsets, apparent distances, position angles, eclipses and occultations of Galilean satellites, bright stars, photometric standard stars, selected X-ray and gamma ray sources, a full list of Observatories, errata and the glossary.

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UK Hydrographic Office, 2006-2021

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