Any of various portable instruments formerly used for making astronomical measurements, esp. the altitudes of celestial objects, typically taking the form of a graduated metal disc with rotating parts and a sighting arm. Also: (more fully mariner’s astrolabe, sea astrolabe) a similar but simpler and heavier instrument, lacking a rete, used for determining latitude at sea from observations of the altitude of a star or the noon sun.


Leave a Reply

Your email address will not be published. Required fields are marked *