Enjoy unlimited access: just £1 for 12 weeks

Subscribe now

The highlight was this 61/2in (17cm) diameter, 17th century Portuguese mariner’s astrolabe from the San Francisco wreck. It was discovered by one of the diving team hidden deep within a gully which had helped to preserve it in relatively unabraded
condition. The instrument is signed Nicola(o) Rvffo and dated 1645 but its most unusual feature is that the entire piece is silver-plated, a unique feature in the known corpus of mariners’ astrolabes. It sold for £110,000 (plus premium) to the Mariners’ Museum in Virginia.