What device was used by early navigators to determine the position of the stars?

• A. The Compass
• B. The Sextant
• C. The Globe
• D. The Astrolabe/Quadrant

Answer: (D)

Tracking where stars sit in the sky is about measuring their angle above the horizon. The devices designed for that early celestial work are the astrolabe and the quadrant. Both let navigators gauge the altitude of a star or the sun, which they then use, along with time and known star positions, to figure out their own latitude and, with accurate time, their longitude. The compass points to magnetic north, not to celestial positions, so it doesn’t tell you where the stars are. A globe is simply a model of the Earth, not a tool for measuring star positions. A sextant can measure angles between stars and the horizon, but it came into widespread use later; the astrolabe and quadrant were the classic early instruments for this purpose.