A yearly publication containing tables of the Sun, Moon, planets, and stars, plus other data for marine navigation, prepared and issued jointly by the US Naval Observatory and HM Nautical Almanac Office. Founded by N. Maskelyne, it was first published in Britain in 1766 (for the year 1767) under the title The Nautical Almanac and Astronomical Ephemeris. In 1914 it was divided into two versions, one for astronomers and an abridged version for navigators; the astronomical version is now known as The Astronomical Almanac. In 1960 The Nautical Almanac merged with The American Nautical Almanac, published separately in the USA since 1914 (for the year 1916). Related publications are The Air Almanac for air navigators and The Star Almanac for land surveyors.

http://astro.ukho.gov.uk/nao/publicat/na.html Official website.