Source : Webster's Revised Unabridged Dictionary (1913)

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.

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

   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.

Sighting \Sight"ing\,
   a. & n. from {Sight}, v. t.

   {Sighting shot}, a shot made to ascertain whether the sights
      of a firearm are properly adjusted; a trial shot.

Source : WordNet®

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