Ancient Tools

Courtesy of Bibliotheque nacional de France

Early astronomers used many kinds of instruments to study the heavens. All were basically tools for measuring or calculating the positions of objects in the sky. With them, astronomers mapped the stars and made tables to predict the future positions of the Sun, Moon, and planets. This knowledge was important, for the sky served as a clock, calendar, and navigational aid. It told farmers when to plant and harvest and helped seafarers find their way. It was used to mark religious observances and to cast horoscopes.