sextant

A sextant is a navigational instrument used to measure the angle between two visible objects, typically used at sea to determine a ship's latitude and longitude. By measuring the angle of the sun or a star above the horizon, sailors can calculate their position on the Earth's surface. The device consists of a graduated arc, a movable arm called an index arm, and mirrors that reflect images for accurate readings. Although modern technology like GPS is common now, sextants were essential tools for navigation before the digital age, demonstrating the principles of celestial navigation.