#eyepiece__ocular  combination of lenses at the viewing end of optical instruments
  supertype:  lens_system__lens  a transparent optical device used to converge or diverge transmitted light and to form images
  part of:  binocular  light_microscope  optical_telescope  sight.optical_instrument
  part:  reticle__graticule  a network of fine lines, dots, cross hairs, or wires in the focal plane of the eyepiece of an optical instrument
     part:  cross_hair__crosshair__cross_wire__crosswire  either of two fine mutually perpendicular lines that cross in the focus plane of an optical instrument and are use for sighting or calibration; "he had the target in his cross hairs"

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