THE EARLIEST known marine navigation tool, discovered in a shipwreck, has been identified thanks to state-of-the-art scanning technology at Warwick University.
Professor Mark Williams at WMG, based at the university, was tasked with scanning the artifact – an astrolabe from the late fifteenth century, used by mariners to measure the altitude of the sun during voyages – which was recovered from the bottom of the Indian Ocean in 2014.
When the Blue Water Recovery team found it they thought it was an astrolabe, but could not see any navigational markings on it, so could not be certain.
They then approached Professor Williams, who conducts pioneering scanning analyses in his laboratory at WMG, to reveal the artefact’s invisible details.
The scans showed etches around the edge, each separated by five degrees, proving it was an astrolabe.
These markings 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.
Professor Williams said:“It was fantastic to apply our 3D scanning technology to such an exciting project and help with the identification of such a rare and fascinating item.
“Usually we are working on engineering-related challenges, so to be able to take our expertise and transfer that to something totally different and so historically significant was a really interesting opportunity.”
The astrolabe is a bronze disc, which measures 17.5cm in diameter, and is engraved with the Portuguese coat of arms and the personal emblem of Don Manuel I, the King of Portugal from 1495 to 1521.
It is believed to date from between 1495 and 1500, and was recovered from the wreck of a Portuguese explorer ship which sank during a storm in the Indian Ocean in 1503.
The ship 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.
David Mearns, from Blue Water Recovery, who led the excavation, said: “It’s a great privilege to find something so rare, something so historically important, something that will be studied by the archaeological community and fills in a gap.”