A modern Iranian-made astrolabe (left). (By Jacopo Koushan (User:Jacopo188)Photograph by Masoud Safarniya (User:M.safarniya) – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=26080692). A mariner’s (AKA sea) astrolabe (right). (By Pearson Scott Foresman – Archives of Pearson Scott Foresman, donated to the Wikimedia FoundationThis file has been extracted from another file: PSF A-50010.png, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2572104)



  • A device for measuring the altitude of celestial bodies.


17th century. Originally from the Greek word, astrolabeon, meaning star taking. Came to English via French and Latin.


An instrument that’s been used since at least classical times and predates the sextant. Essentially a model of the sky and functions as an inclinometer. There are different types of astrolabes for either astronomical or marine purposes (see above images). The history and use of these devices is best suited for a dedicated article.


Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport.