sekstanten

A sekstant is a precision navigational instrument used primarily for celestial navigation and surveying. It is a modified version of the octant, designed to measure angles up to 60 degrees (one-sixth of a full circle, or 360 degrees), hence its name. The sekstant was developed in the early 18th century as an improvement over earlier instruments like the quadrant and octant, offering greater accuracy and ease of use.

The sekstant operates on the principle of double reflection, allowing the observer to measure the angle between two objects, such as a celestial body and the horizon. The instrument consists of a fixed arc marked with degrees, a movable mirror (the index mirror), and another fixed mirror (the horizon mirror). The observer aligns the celestial body with the horizon mirror, then adjusts the index mirror until the reflected image of the body coincides with its direct reflection. The angle is then read directly from the arc.

Sekstants were widely used by navigators, sailors, and explorers before the advent of electronic navigation systems. They played a crucial role in maritime and aerial navigation, enabling precise determination of latitude and longitude by measuring the altitude of stars, the sun, or the moon. The instrument’s portability and durability made it indispensable for long voyages and expeditions.

Over time, the sekstant was gradually replaced by electronic devices such as the sextant (a modern term sometimes used interchangeably but technically distinct) and GPS systems. However, it remains a valuable tool in education, historical preservation, and as a backup for traditional navigation methods. Today, sekstants are primarily used for training purposes and in recreational sailing to teach celestial navigation techniques.