Scientific research, timekeeping, calendars, and navigation have all depended upon the practical skills of positional astronomy for thousands of years. Today, in the United States, the U.S. Naval Observatory produces the data for celestial navigation and positional astronomy on behalf of the nation.

As part of this responsibility, and in a long-standing collaboration with Her Majesty's Nautical Almanac Office in the United Kingdom, the Nautical Almanac Office at the U.S. Naval Observatory produces several annual almanacs. Each edition contains data for one year and is published nine months or more in advance of that date. Her Majesty's Nautical Almanac Office maintains the copyright on the material it contributes.

• The Astronomical Almanac contains precise positions (ephemerides) of most solar system objects, data for eclipses and other astronomical phenomena, and catalogs of selected celestial objects.
• The Astronomical Almanac Online contains complementary information found in the printed Astronomical Almanac.
• The Nautical Almanac contains the astronomical data required for marine celestial navigation.
• The Air Almanac contains the astronomical data required for air celestial navigation.
• Astronomical Phenomena contains selected data of general interest data from The Astronomical Almanac. It is available two years in advance.
• Ordering Information contains instructions on how to order the above publications.