The nautical astrolabe, in comparative terms, was for its time what the GPS is for ours, and the Maritime Museum has the largest collection of nautical astrolabes in the world.The astrolabe "Atocha III" is one example of that. Was found in 1985 in the wreckage of the ship Nuestra Señora de Atocha, sunk in 1622 in the shallows of Key West (USA). It bears an inscription with the date of manufacture, 1605, and the letter "G", used by the Góis (a Portuguese family of astrolabe makers