Nautical Astrolabe Keychain
This piece is a reproduction of the Dundee nautical astrolabe. This marine astrolabe, made by the Portuguese and dated between 1550 and 1555, is preserved in the Art Gallery and Museum in Dundee, Scotland.
The nautical astrolabe is a simplified version of the planispheric (or astronomical) astrolabe. It only allows for measuring the height of stars and was used to calculate latitude.