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The Sextant: Navigating The Old Way
Hackaday • • science
Key Points:
- The sextant is a traditional navigational instrument that measures the angle between a celestial body and the horizon, allowing sailors to determine their position at sea with reasonable accuracy before modern GPS technology.
- It operates using a frame, two mirrors, and a telescope to view the horizon and celestial object simultaneously, utilizing double reflection to measure angles up to 120 degrees with precision down to 0.1 minutes of angle.
- By referencing the measured angle and exact time in a nautical almanac, navigators can calculate latitude and longitude, typically achieving positional accuracy within a few nautical miles.
- The sextant’s design compensates for the motion of a ship at sea, as both the horizon and celestial object move together, enabling reliable readings even on a heaving deck.
- Despite modern GPS systems being faster and more accurate, sextants remain in use as a reliable backup for navigation, especially in situations where electronic systems may fail or be jammed.
