Navigation and nautical astronomy

Nautical Astronomy a branch of practical astronomy that answers the needs of navigation. Nautical astronomy is concerned with developing methods for determining from celestial bodies and navigational, artificial earth satellites the position of a ship at sea and corrections for course-indication instruments. Nautical astronomy is part of the science of navigation.The position of a ship at sea, that is, its geographic latitude ? and longitude ?, is determined by measuring the altitudes of celestial bodies over the visible sea horizon or over the plane of an artificial horizon created on the ship by different methods. The use of angle-measuring devices with an artificial horizon has expanded the possibilities for determining ship positions by astronomical means and has also increased the precision in measuring altitudes of celestial bodies.