An astrolabe is an ancient astronomical instrument used for solving problems related to time and the position of celestial bodies. It consists of a flat disk with a rotating arm, called an alidade, which helps users measure angles between stars and the horizon. Astrolabes were widely used by astronomers, navigators, and explorers, particularly during the Middle Ages and the Renaissance. The device can also be used to determine local latitude by measuring the altitude of the Sun or stars. Astrolabes played a crucial role in the development of navigation and astronomy, influencing the work of notable figures like Ptolemy and Ibn al-Haytham.