Nautical Navigation

How to Navigate in Ancient Times

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Astrolabe
A brilliant device used to determine Latitude by observing the altitude and position of the sun, stars, or other planets.

Backstaff
The Back Staff or Back Quadrant is an navigational instrument that was used to determine latitude by measureing the altitude of the sun in the sky.

Compass
The most influential invention ever given to the age of Exploration - The Mariner's Compass!

Compass Rose
Brief history of how the little illustration found on a map or chart identifying the different points of direction came to be.

Cross Staff
Simple land surveying tool adopted for navigational use at sea

Lead Line
A weighted line, knotted at fathoms, lowered from the deck of a ship to determine water depth and to take samples from the bottom.

Log Line
Knotted cord that runs out from a reel to a piece of wood, used to gauge the speed of a vessel at sea.

Nocturnal
Navigational Instrument used to observe certain stars relative to the pole star in Ursa Minor, enabling you to discover the hour at night.

Quadrant
Rare medieval navigational instrument that combined the features of an astrolabe and a quadrant

Reflecting Circle
19th century navigational instrument in the form of a graduated circle, used at sea to find the longitude by measuring the distance between the spotter and the moon.

Sand Glass
(a.k.a., Hour glass, sand timer or sand clock)
Information on this clever little device, used to keep time in the age of sail.

The Sextant
The pinnacle of nautical navigation, the sextant has been used for almost 300 years - even by NASA Gemini missions!

Traverse Board
Early device used to calculate speed, distance, direction and other navigational essentials in the 16th century.

The H1, H2, H3, & ultimately the H4
The story of John Harrison and how he came to invent the tools and methodology to determine a ship's longitude while at sea.  His inventions revolutionized sea travel for more than 250 years!

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