Astrolab (dated century): This was for measuring the altitude of heavenly bodies above the horizon, and so determining (among other things) the time of day or night. Readings are taken by means of rotatable alidade, a diametrical rule with sights.
Astrolabe – Magnificent Computer of the Ancients ~ Kuriositas This invention changed everything for the first time, we could know the time, the day and when the sun would rise and set. Lost to the west after the fall of Rome.
Vintage & Astrolabe – Ancient instrument for locating and predicting the positions of the Sun, Moon, planets, and stars. The earliest astrolabe was created 150 B. Was an indispensable tool of astronomers, navigators and astrologers. on imgfave