: a compact instrument used to observe and calculate the position of celestial bodies before the invention of the sextant
"His astrolabe of silver was the gift of the Emperor of Germany…." — Sir Walter Scott, Quentin Durward, 1823
"The astrolabe, whose invention is often attributed to the Greek astronomer Hipparchus, places the Earth at the center of the universe, with all celestial bodies orbiting around it." — Grégory Gardinetti, CNN.com, 6 Jan. 2016
Did You Know?
"Thyn Astrolabie hath a ring to putten on the thombe of thi right hond in taking the height of thinges." Thus begins a description of the astrolabe in A Treatise on the Astrolabe, a medieval user's guide penned by an amateur astronomer by the name of Geoffrey Chaucer. Chaucer is best known for his Middle English poetic masterpiece The Canterbury Tales, but when his nose wasn't buried in his writing, Chaucer was stargazing, and some of his passion for the heavens rubbed off on his son Lewis, who had displayed a special "abilite to lerne sciences touching nombres and proporciouns." Chaucer dedicated his treatise to the 10-year-old boy, setting his instructions not in the usual Latin, but in "naked wordes in Englissh" so that little Lewis could understand. When he got older, Lewis may have learned that the word astrolabe traces to the Greek name for the instrument.
Test Your Vocabulary
Unscramble the letters to create the name for an instrument for observing altitudes of a celestial body from a moving ship or aircraft: NCATTO.VIEW THE ANSWER