In seafaring, a quadrant refers to a navigational instrument used for measuring the angle of elevation of a celestial body above the horizon. It is specifically designed for celestial navigation, allowing sailors to determine their latitude by measuring the altitude of the sun, stars, or other celestial bodies.
A quadrant typically consists of a graduated arc of 90 degrees, one-fourth of a full circle, hence the name "quadrant." The instrument is divided into degrees, minutes, and sometimes even seconds. Navigators would use the quadrant to measure the angle between the celestial body and the horizon. By knowing the angle and the time of observation, sailors could then calculate their latitude using navigational tables or mathematical formulas.
They are no longer in general use as modern navigation relies more on instruments like sextants and electronic devices such as GPS, but the concept of measuring celestial angles with a quadrant contributes more... to the historical understanding of navigation techniques at sea. less...
An early 20th century quadrant lever balance scale, the cast steel base marked 'G & G', with brass column and arc scale graduated from 0 to 250gms. Height 13.39 in.