Astrolabe

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Astrolabe \As"tro*labe\ ([a^]s"tr[-o]*l[=a]b), n. [OE.
     astrolabie, astrilabe, OF. astrelabe, F. astrolabe, LL.
     astrolabium, fr. Gr. 'astrola`bon; 'a`stron star + ?, ?, to
     take.]
     1. (Astron.) An instrument for observing or showing the
        positions of the stars. It is now disused.


        [1913 Webster]
  
     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 It is now superseded by the quadrant and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.
           [1913 Webster]
  
     2. A stereographic projection of the sphere on the plane of a
        great circle, as the equator, or a meridian; a
        planisphere. --Whewell.
        [1913 Webster]

From WordNet (r) 2.0 [wn]:

  astrolabe
       n : an early form of sextant