Author: UK Hydrographic Office
Published: April 2025
NP314-25
The Nautical Almanac contains astronomical information to support bridge crews in routine and emergency celestial navigation, as well as the calculation of daylight hours and mandatory gyro checks. It is carried on every ship within the Royal Navy and is at the core of celestial navigational training courses worldwide.
The Nautical Almanac includes:
- Tabulations of the Sun, Moon, navigational planets and stars to help determine positions at sea when using a sextant
- Times of sunrise, sunset, twilights, moonrise and moonset, phases of the Moon and eclipses of the Sun and Moon to help bridge crews plan observations
- Interpolation and altitude correction tables, pole star tables and diagrams, and notes for the identification of stars and planets
- Information on standard times for countries around the world
- A concise set of sight reduction tables and sight reduction forms
