In 1492 when Columbus crossed the Atlantic, although latitude could be measured (typically from observations of the Pole Star), there was no reliable way of measuring a ship’s longitude once out of sight of land. Charts were inaccurate and incomplete and much of the World remained unexplored. This article explores the various ideas for measuring longitude, using everything from the Moon to the satellites of Jupiter to the need for royal observatories.
The Quest for Longitude and the Rise of Greenwich
