The Nautical Almanac
For over 150 years the United States Nautical Almanac Office has published
The Nautical Almanac, first as part of the American Ephemeris and
Nautical Almanac, and then on its own, to provide the US Navy with a
convenient form of the astronomical data used for celestial navigation.
This book is still the standard resource for marine celestial navigation for
the U.S. Navy.
The history of The Nautical Almanac is found
The book contains the following data tabulated at hourly intervals
to a precision of 0.1 arcminute: the Greenwich hour angle and declination of the
Sun, Moon, and navigational planets; the Greenwich hour angle of Aries;
positions of the navigational stars; rise and set times of the Sun and Moon for
a range of latitudes; and other data. Each edition also contains a sight
reduction table; sight reduction formulas; and various correction tables for
sight reduction. There is a useful concise sight reduction form at the back of
the book. The Nautical Almanac is available nine months in advance of its
The book is produced in collaboration with
Her Majesty's Nautical Almanac Office
in the UK. That office
maintains the copyright on the material it produces.
Some links of interest
for The Nautical Almanac: