Astrolabe: Shipwreck find 'earliest navigation tool'

An artefact excavated from a shipwreck off the coast of Oman has been found to be the oldest known example of a type of navigational tool.

Marine archaeologists say the object is an astrolabe, an instrument once used by mariners to measure the altitude of the Sun during their voyages. It is believed to date from between 1495 and 1500.

The item was recovered from a Portuguese explorer which sank during a storm in the Indian Ocean in 1503. The boat was called the Esmeralda and was part of a fleet led by Portuguese explorer Vasco da Gama, the first person to sail directly from Europe to India.

Laser scanning work carried out by scientists at the University of Warwick revealed etches around the edge of the disc, each separated by five degrees. This would have allowed mariners to measure the height of the sun above the horizon at noon to determine their location so they could find their way on the high seas. 
 

UCJ, UNILORIN.