This is a mariner's astrolabe. long ago, if the captain of a ship wanted to go to a known place, the captain would sail to the latitude of the location and then sail east or west along the latitude line until the place was reached. for this kind of navigation, the captain might use an astrolabe: it was used to determine the ship's by using measuring the noon altitude of the sun or the altitude of a star. a) speed b) latitude c) direction, east or west d) distance from home port