A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea.
The Almanac specifies for each whole hour of the year the position on the Earth’s surface (in declination and Greenwich hour angle) at which the sun, moon, planets and first point of Aries is directly overhead. The positions of 57 selected stars are specified relative to the first point of Aries.
- Published every year and it contains tabulated data of the entire year for the practice of astronomical navigation at sea.
- function has also been provided to use the almanac of the previous year for the subsequent year in case the supply of the almanac has been delayed on board.
Contents of Nautical Almanac:-
The Nautical Almanac contains tabulations of the Sun, Moon, navigational planets and stars for use in the determination of position at sea from sextant observations. In addition, it gives times of sunrise, sunset, twilights, moonrise and moonset, phases of the Moon and eclipses of the Sun and Moon for use in the planning of observations. All the necessary interpolation and altitude correction tables are provided as well as pole star tables and diagrams and notes for the identification of stars and planets. Information on standard times for most countries around the world is provided. A concise set of sight reduction tables and a sight reduction form are also included.