Lunar Distance Method

The Lunar Distance Method is a technique navigators used before modern GPS to determine their longitude at sea. It involves measuring the angle between the Moon and a specific star or the Sun, then comparing this measurement to published lunar distance tables. By knowing the precise time of the measurement, navigators can find the Moon's position relative to the stars, allowing them to calculate their exact longitude. This method was essential for accurate navigation before electronic systems, relying on careful observation, precise timing, and detailed astronomical tables.