A Nautical Almanac is a publication that provides essential information for navigation at sea. It includes data on celestial bodies, such as the positions of the Sun, Moon, and stars, which sailors use to determine their location. The almanac is updated annually to ensure accuracy. In addition to celestial positions, the Nautical Almanac contains information on tides, currents, and other navigational aids. It is a crucial tool for mariners, helping them to plot their courses and ensure safe travel across oceans and seas.