In the 18th century, determining longitude while sailing across the open ocean was a significant challenge. Latitude, the distance north or south of the equator, could be relatively easily measured using the position of the stars. However, calculating longitude, the distance east or west of a reference point, was much more complex. It required knowing the precise time at a known location and comparing it to the local time at the ship's current location.
The British government offered a substantial reward, known as the Longitude Prize, for anyone who could devise a reliable method for determining longitude at sea. Numerous attempts were made using celestial observations, lunar distances, and other methods, but none proved accurate or practical enough for widespread use.
In the mid-18th century, an English clockmaker named John Harrison embarked on a mission to create a reliable marine timepiece, or chronometer, that could accurately measure time at sea. Harrison was no ordinary clockmaker; he was a self-taught genius with an innovative mind and an unwavering determination.