Astrolabe

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Not to be confused with cosmolabe.

For other pages with a similar name, see Astrolabe (disambiguation).

For a list of ships, see French ship Astrolabe.

A modern astrolabe made in Tabriz, Iran in 2013.

The spherical astrolabe from medieval Islamic astronomy, c. 1480, in the Museum of the History of Science, Oxford^[1]

An astrolabe made of gilded brass from about 1540–70.

The Canterbury Astrolabe Quadrant, England, 1388.

A 16th-century astrolabe showing a tulip rete and rule.

An astrolabe (Greek: ἀστρολάβος astrolabos; Arabic: ٱلأَسْطُرلاب‎ al-Asturlāb; Persian: اَختِرِیاب‎ Akhtaryab) is an elaborate inclinometer, historically used by astronomers and navigators to measure the inclined position in the sky of a celestial body, day or night. The word astrolabe means "the one that catches the heavenly bodies."^[2] It can thus be used to identify stars or planets, to determine local latitude given local time (and vice versa), to survey, or to triangulate. It was used in classical antiquity, the Islamic Golden Age,^[3] the European Middle Ages and the Age of Discovery for all these purposes.

The astrolabe's importance not only comes from the early development of astronomy,^[2] but is also effective for determining latitude on land or calm seas. Although it is less reliable on the heaving deck of a ship in rough seas, the mariner's astrolabe was developed to solve that problem.