Archeologists Discover Oldest Known Marine Navigational Tool From Shipwreck, Belonged to Vasco Da Gama's Fleet

In 2014, archeologists uncovered an ancient specimen of one of the oldest known marine navigation tools used by humans from a shipwreck off the coast of Oman. The tool in question is an astrolabe, an ancient instrument used by sailors to figure out the sun's altitude during their journey, stated BBC. The astrolabe was found on a ship Esmeralda and could have been made somewhere between 1495 and 1500.

Esmeralda was a Portuguese ship that reportedly sank in the Indian Ocean in 1503. The ship was part of a fleet led by the legendary explorer, Vasco da Gama. "It's a great privilege to find something so rare, something so historically important, something that will be studied by the archeological community and fills in a gap," David Mearns, an official from Blue Water Recovery, who led the excavation effort stated. Astrolabe was among the 3,000 artifacts, the team recovered from the ship.

Officials from Blue Water Recovery were not initially sure the Bronze disc they had uncovered was an astrolabe. The item in their custody was noted to be 17.5cm in diameter and around 2mm in thickness. There were also two emblems on the artifact. "It was like nothing else we had seen and I immediately knew it was something very important because you could see it had these two emblems on it," said Mr Mearns. "One I recognized immediately as a Portuguese coat of arms... and another which we later discovered was the personal emblem of Don Manuel I, the King of Portugal at the time."

From its appearance, the officials guessed it was an astrolabe but could not spot the navigational marking to confirm their assertion. The likely astrolabe was sent to the University of Warwick in England for analysis, according to Smithsonian Magazine. Researchers in the institution used 3-D scanning technology and found some etches around the edge. Each of the markings was separated by five degrees. The markings aided mariners in understanding at what height the sun was above the horizon, during the afternoon. Based on this finding sailers made decisions regarding the route they would undertake in their voyages. The artifact is likely the earliest specimen of a mariner's astrolabe uncovered by researchers.

The astrolabe located in Esmeralda is the 108th confirmed specimen of this tool, as per BBC. Researchers figured out the origin of this tool based on the ship in which it was uncovered and the emblems that were made on it. "We know it had to have been made before 1502, because that's when the ship left Lisbon and Dom Manuel didn't become King until 1495, and this astrolabe wouldn't have carried the emblem of the King unless he was King. I believe it's probably fair to say it dates roughly to between 1495 to 1500. Exactly what year we don't know - but it is in that narrow period," Mearns said.

The finding has been considered crucial by experts, as it confirms historical records detailing the rise of the mariner’s astrolabe, stated Smithsonian Magazine. Portuguese historian, João de Barros, in one of the historical documents reportedly claimed that da Gama used a wooden astrolabe in a 1497 expedition to Saint Helena. The discovery backs up this writing and further establishes that da Gama's crew was using the technology in the late 15th or early 16th Century.