Transcription: Here's how the quadrant worked. Its base would be aligned with the horizon, with the movable arm pointing at the sun or north star. The arm of the quadrant would indicate the angle between the horizon and the star. Using this angle, the navigator could calculate his latitude on the globe. But celestial navigation was only partially effective. Instruments were inexact. If clouds obscured the stars and sun, a reading would be impossible. And there was no way way to determine longitude.
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