An astrolabe from Passa Pau, Cape Verde Islands

Mariner's astrolabes seem to have been in use from the 15th to the end of the 18th centuries. They evolved at about the same time as quadrants and cross- staffs. Their precursor, the astronomer's astrolabe and kamal, were either too cumbersome or not sufficiently accurate for sea-going use. an astrolabe found on the Passa Pau wreck is unique in that it is the only known specimen coated with silver. It is dated 1645 and has the maker's name, Nicolao Rvffo, inscribed on it.