Tag Archives: Longitude

Calculating Changes in Longitude and Time Along a Parallel of Latitude.

If two ships are both positioned exactly on the Equator but are separated by 900 nautical miles in an east/west direction, then in terms of longitude, they will be 15o apart and in terms of Greenwich Mean Time, they will be … Continue reading

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Lunar Distance

  With the invention of the chronometer in 1759, mariners were, for the first time, able to calculate longitude by finding the difference between Greenwich Mean Time and Local Time.  However, the marine chronometer did not become affordable until around … Continue reading

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