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2 definitions found
 for Binocular parallax
From The Collaborative International Dictionary of English v.0.48 :

  Optic \Op"tic\ ([o^]p"t[i^]k), Optical \Op"tic*al\
     ([o^]p"t[i^]*kal), a. [F. optique, Gr. 'optiko`s; akin to
     'o`psis sight, 'o`pwpa I have seen, 'o`psomai I shall see,
     and to 'o`sse the two eyes, 'o`ps face, L. oculus eye. See
     Ocular, Eye, and cf. Canopy, Ophthalmia.]
     1. Of, pertaining to, or using vision or sight; as, optical
        illusions. [WordNet sense 2]
     Syn: ocular, optic, visual.
          [1913 Webster + WordNet 1.5]
                The moon, whose orb
                Through optic glass the Tuscan artist views.
          [1913 Webster]
     2. Of or pertaining to the eye; ocular; as, the optic nerves
        (the first pair of cranial nerves) which are distributed
        to the retina; the optic (or optical) axis of the eye. See
        Illust. of Brain, and Eye. [WordNet sense 3]
        [1913 Webster]
     3. Relating to the science of optics or to devices designed
        to assist vision; as, optical works; optical equipment.
        [WordNet sense 1]
        [1913 Webster +PJC]
     Optic angle (Opt.), the angle included between the optic
        axes of the two eyes when directed to the same point; --
        sometimes called binocular parallax.
     Optic axis. (Opt.)
        (a) A line drawn through the center of the eye
            perpendicular to its anterior and posterior surfaces.
            In a normal eye it is in the direction of the optic
            axis that objects are most distinctly seen.
        (b) The line in a doubly refracting crystal, in the
            direction of which no double refraction occurs. A
            uniaxial crystal has one such line, a biaxial crystal
            has two.
     Optical circle (Opt.), a graduated circle used for the
        measurement of angles in optical experiments.
     Optical square, a surveyor's instrument with reflectors for
        laying off right angles.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 :

  Parallax \Par"al*lax\, n. [Gr. ? alternation, the mutual
     inclination of two lines forming an angle, fr. ? to change a
     little, go aside, deviate; para` beside, beyond + ? to
     change: cf. F. parallaxe. Cf. Parallel.]
     1. The apparent displacement, or difference of position, of
        an object, as seen from two different stations, or points
        of view.
        [1913 Webster]
     2. (Astron.) The apparent difference in position of a body
        (as the sun, or a star) as seen from some point on the
        earth's surface, and as seen from some other conventional
        point, as the earth's center or the sun.
        [1913 Webster]
     3. (Astron.) The annual parallax. See annual parallax,
     Annual parallax, the greatest value of the heliocentric
        parallax, or the greatest annual apparent change of place
        of a body as seen from the earth and sun; it is equivalent
        to the parallax of an astronomical object which would be
        observed by taking observations of the object at two
        different points one astronomical unit (the distance of
        the Earth from the sun) apart, if the line joining the two
        observing points is perpendicular to the direction to the
        observed object; as, the annual parallax of a fixed star.
        The distance of an astronomical object from the Earth is
        inversely proportional to the annual parallax. A star
        which has an annual parallax of one second of an arc is
        considered to be one parsec (3.26 light years) distant
        from the earth; a star with an annual parallax of
        one-hundredth second of an arc is 326 light years distant.
        See parsec in the vocabulary, and stellar parallax,
     Binocular parallax, the apparent difference in position of
        an object as seen separately by one eye, and then by the
        other, the head remaining unmoved.
     Diurnal parallax or Geocentric parallax, the parallax of
        a body with reference to the earth's center. This is the
        kind of parallax that is generally understood when the
        term is used without qualification.
     Heliocentric parallax, the parallax of a body with
        reference to the sun, or the angle subtended at the body
        by lines drawn from it to the earth and sun; as, the
        heliocentric parallax of a planet.
     Horizontal parallax, the geocentric parallx of a heavenly
        body when in the horizon, or the angle subtended at the
        body by the earth's radius.
     Optical parallax, the apparent displacement in position
        undergone by an object when viewed by either eye singly.
        --Brande & C.
     Parallax of the cross wires (of an optical instrument),
        their apparent displacement when the eye changes its
        position, caused by their not being exactly in the focus
        of the object glass.
     Stellar parallax, the annual parallax of a fixed star.
        [1913 Webster]

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