Hip Glossary: Astrolabe

The astrolabe is a historical astronomical instrument used by classical astronomers and astrologers. It was the chief navigational instrument until the invention of the sextant in the 18th century. Its many uses included locating and predicting the positions of the Sun, Moon, planets and stars; determining local time given local longitude and vice-versa; surveying; and triangulation. Astrologers of the Islamic world and European nations used astrolabes to construct horoscopes.