LONGITUDE
Longitude is the angular coordinate that measures the position of a point east or west of the reference meridian (Greenwich meridian, 0°), from –180° to +180°. Determining it at sea was for centuries one of the great challenges of navigation: unlike Latitude, which can be measured by direct observation of the Sun or stars, Longitude requires knowing the exact time at the origin meridian at the moment of local observation. It is this necessity that led to the development of marine chronometers in the 18th century, notably by John Harrison (H1 to H5) and Ferdinand Berthoud. A four-minute error in measuring Time resulted in a one-degree error in Longitude, or about 111 kilometers at the equator. Solving the Longitude problem profoundly shaped the history of horology, making chronometric precision a matter of maritime survival and an unprecedented driver of technical innovation.
This page has been automatically translated from the reference French version using an artificial intelligence tool. Errors or inaccuracies may remain. If you notice any, especially if this is your native language, please feel free to report them to us at info@horopedia.org. Your contribution helps us improve the quality of the encyclopedia.
Pending their translation, images and videos remain temporarily displayed in French.
Thank you for your understanding.