World’s oldest known marine astrolabe found in a 500-year old shipwreck

oldest-marine-astrolabe-shipwreck_1Credit: Philip Koch

Esmeralda, a ship that was originally a part of the fleet led by Vasco da Gama (the first known European to sail directly from his homeland Portugal to India), met its ‘demise’ in circa 1503 AD at the figurative hands of a brutal storm. An underwater excavation conducted back in 2014 (by Blue Water Recovery) unraveled a bevy of artifacts and objects from the pertinent shipwreck, including what was then an unidentified bronze disk. And after three years, researchers at the University of Warwick have finally been able to discern this specimen with the aid of a 3D-imaging scanner. The contraption revealed several etchings on the disk that pretty much confirm that the object was used as an astrolabe – a marine navigation tool.


Credit: University of Warwick

These markings in question were found around the edge of the object, with each etching being separated by 5 degrees. To that end, the astrolabe helped mariners to measure the height of the sun above the horizon during noon time, which in turn could specify their location on the sea. Professor Mark Williams, who was instrumental in identifying the object, and is also considered as an expert in the field for his pioneering scanning assessments, 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.


Credit: University of Warwick

Now from the historical perspective, this almost 7-inch-diameter (17.5 cm) disc pertains to the oldest known marine astrolabe (and it dates from between circa 1495-1500 AD). And complementing its legacy as a scientific object is a series of intricate engravings that bear the Portuguese coat of arms and the personal royal emblem of Don Manuel I, the King of Portugal who reigned from 1495-1521. David Mearns, from Blue Water Recovery, who originally headed the excavation, commented –

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.


Credit: University of Warwick

Source: University of Warwick