Trivia: Sailors used astrolabes and sextants to measure what?
Correct Answer: Celestial objects
So why is this answer correct? : Astrolabes and sextants, while both instruments used by sailors to navigate using the stars, have slightly different functions. Astrolabes, used by both Greek and Arab sailors, were multi-purpose instruments that measured the altitude of celestial objects, determined latitude and longitude, and surveyed distance, among other objectives. A sextant, while similar, specifically measured the distance between two celestial objects for the purpose of navigation. Both were indispensable instruments on the high seas long before the days of satellite navigation.