Using a Sextant
What is a Sextant? Sextants are commonly used in marine navigation and aviation. A sextant is a valuable instrument used to determine the angle between the horizon and a celestial body like the Sun, Moon, or Star. It is used in celestial navigation to calculate latitude and longitude. The instrument consists of a graduated arc, a sighting mechanism, and a movable index arm that is used to measure the angle between two objects. A mirror is placed on the radial arm. It is moved or adjusted until the celestial body is reflected into a half-silvered mirror in line with the telescope and appears to coincide with the horizon through the telescope. The angular distance of the celestial body or star above the horizon is read from the graduated arc of the sextant. Celestial navigation continues to be used by private yachtsmen, and particularly by long-distance cruising yachts around the world. For small cruising boat crews, celestial navigation is generally considered an e...