sekstantit

The sekstantit is a measuring instrument used to determine the angle between two visible objects. It is most commonly used for celestial navigation to measure the angle between a celestial body (such as the Sun or a star) and the horizon. This angle, known as the altitude, is crucial for calculating a navigator's position.

The name "sekstantit" comes from the Latin word "sextans," meaning one-sixth of a circle, as the arc of the instrument typically covers 60 degrees. It consists of a frame, a sighting telescope, a horizon mirror, an index mirror, and a graduated arc with a vernier scale. The user looks through the telescope at the horizon and simultaneously adjusts the index mirror until the celestial body appears to rest on the horizon. The angle is then read from the arc.

While sextants were historically made of brass or wood, modern versions are often constructed from lighter and more durable materials like aluminum or plastic. Despite the advent of electronic navigation systems like GPS, the sekstantit remains a valuable tool for backup navigation, as it does not rely on external power sources or signals. Its simplicity, reliability, and educational value ensure its continued use by mariners, aviators, and surveyors.