1. Planning Passages
(Mariners Education/Navigation)

... the voyage has begun the progress of the vessel along its planned route must be monitored. This requires that the ship's position be determined, using standard methods including dead reckoning, celestial ...

2. Navigational History
(Mariners Education/Navigation)

... was invented. The sextant was derived from the octant in 1757 in order to provide for the lunar distance method. With the lunar distance method, mariners could determine their longitude accurately. Once ...

3. Marine Navigation
(Mariners Education/Navigation)

... 151° east. New York City has a longitude of about 74° west. For most of history, mariners struggled to determine precise longitude. The problem was solved with the invention of the marine chronometer. ...