A simplified illustration o the parallax o an object against a distant backgrund due tae a perspective shift. When viewed frae "Viewpynt A", the object appears tae be in front o the blue squerr. When the viewpoint is chynged tae "Viewpoint B", the object appears tae have moved in front o the reid squerr.

Parallax is a displacement or difference in the apparent poseetion o an object viewed alang twa different lines o sicht, an is measured bi the angle or semi-angle o inclination atween those twa lines.[1][2]


  1. Shorter Oxford English Dictionary. 1968. Mutual inclination of two lines meeting in an angle Missing or empty |title= (help)
  2. "Parallax". Oxford English Dictionary (Second ed.). 1989. Astron. Apparent displacement, or difference in the apparent position, of an object, caused by actual change (or difference) of position of the point of observation; spec. the angular amount of such displacement or difference of position, being the angle contained between the two straight lines drawn to the object from the two different points of view, and constituting a measure of the distance of the object.