as·tro·labe /ˈæstrəˌleb ||ˌlæb/
古代的天體觀測儀
As·tro·labe n.
1. Astron. An instrument for observing or showing the positions of the stars. It is now disused.
Note: ☞ Among the ancients, it was essentially the armillary sphere. A graduated circle with sights, for taking altitudes at sea, was called an astrolabe in the 18th century. It is now superseded by the quadrant and sextant.
2. A stereographic projection of the sphere on the plane of a great circle, as the equator, or a meridian; a planisphere.
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astrolabe
n : an early form of sextant