Spanish Armada-era astrolabe returns to Scilly after mysterious global journey

Navigation aid from 16th century was on seabed for centuries before being bought and sold in US and Australia

It spent hundreds of years languishing on the seabed off the Isles of Scilly in the far south-west of Britain before being hauled back to the surface by divers and setting off a circumnavigation of the world.

Finally the Pednathise Head astrolabe - a rare example of a 16th-century navigational instrument once used by sailors to determine latitude - is back on Scilly after being rediscovered on the other side of the Atlantic.