The Collaborative International Dictionary of English v.0.48:

Sight \Sight\, v. t. [imp. & p. p. Sighted; p. pr. & vb. n.
   Sighting.]
   1. To get sight of; to see; as, to sight land; to sight a
      wreck. --Kane.
      [1913 Webster]

   2. To look at through a sight; to see accurately; as, to
      sight an object, as a star.
      [1913 Webster]

   3. To apply sights to; to adjust the sights of; also, to give
      the proper elevation and direction to by means of a sight;
      as, to sight a rifle or a cannon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sighting \Sight"ing\,
   a. & n. from Sight, v. t.
   [1913 Webster]

   Sighting shot, a shot made to ascertain whether the sights
      of a firearm are properly adjusted; a trial shot.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sighting
    n 1: the act of observing; "several sightings of enemy troops
         were reported"