Celestial fix

A celestial fix is the position fixed by the intersection of two or more celestial lines of position. Each line comes from one sight, reduced by the intercept method to a segment perpendicular to the body’s azimuth at the intercept point. Two crossing lines give a fix; three or more usually form a small cocked hat, and the navigator takes the position from inside it. Because sights are taken minutes apart while the ship moves, each line is advanced or retired along the course and speed to a common time, the same running-fix transfer used with terrestrial bearings. Dawn and dusk star sights yield the strongest fixes.