This book contains detailed information for the year 1981, on the positions of the Sun, Moon, Planets, Stars, and other vital information used in Celestial Navigation .
A new updated edition is published every year by the US and British Governments.
The Nautical Almanac for the year 1981 is still very relevant now because the US Coast Guard currently uses this edition of the Almanac for all its Examination questions for Celestial Navigation testing for Oceans endorsements on a Mariners License.