Vasco da Gama’s India armada reveals oldest navigation tool
Work at the University of Warwick on the object, recovered from the wreck of the ship Esmeralda that sank in the Indian Ocean in 1503, showed it was an astrolabe from the late 15th century.world Updated: Oct 25, 2017 20:16 IST
Cutting edge technology in a UK university department founded by engineer Kumar Bhattacharyya has revealed that an item recovered from a ship in Portuguese explorer Vasco da Gama’s armada to India in the 16th century is the earliest known maritime navigation tool.
Work at Bhattacharyya’s Warwick Manufacturing Group (WMG) on the object, recovered from the wreck of the ship Esmeralda that sank in the Indian Ocean in 1503, showed it was an astrolabe from the late 15th century, used by mariners to measure the altitude of the sun while at sea. The Esmeralda was captained by da Gama’s uncle.
Based at the University of Warwick, WMG has close links with India’s Tata group, and provides research, education and knowledge transfer in engineering, manufacturing and technology. The object was recovered by Blue Water Recovery, a deep sea shipwreck recovery company.
When the object was found, there were no visible navigational markings on it. The recovery team approached Mark Williams of WMG, who conducts pioneering scanning analyses, a university statement said.
His scans showed etches around the edge of the object, each separated by five degrees – proving that it was an astrolabe. The 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.
The technology was able to accurately scan the item to within 0.1 mm and reproduce a high-resolution 3D model. The astrolabe is a bronze disc, measuring 17.5 cm in diameter. It is engraved with the Portuguese coat of arms and the personal emblem of Don Manuel I, the King of Portugal during 1495-1521.
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.”
David Mearns of Blue Water Recovery, who led the excavation in Oman, 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. It was like nothing else we had seen…it adds to the history, and hopefully astrolabes from this period can be found."
The astrolabe is currently with Oman’s national museum.
Da Gama was the first European to reach India by sea, setting the stage for the global expansion of the Portuguese empire. In India, the empire had a colony in Goa from 1510 to 1961.