Abstract: There is provided an improved night vision goggle having a housing containing an objective lens assembly, an image intensifier tube, a collimator assembly, a splitter member, and a pair of afocal telescopes. The optical axis of the afocal telescopes are offset from the optical axis of the collimator and objective lens assemblies. A pair of achromatic doublet lens assemblies are mounted side-by-side on the exit side of the collimator and near the entrance pupils of the telescopes. The optical axes of the doublet lens assemblies are coaxial with the optical axes of the telescopes. The achromatic doublet lens assemblies thus collect light from a sub-diameter, decentered aperture of the collimator assembly, and correct axial chromatic aberration in the telescopes.

Abstract: A binocular or other optical viewing instrument dedicated for eyeglass-wearing users. An extended optical eye relief, as compared to binoculars for those without glasses, provides an eyeglass-wearing user with an optimal wide field of view. A pair of soft rubber eyeglass guards cushion the binocular against the user's eyeglasses, both protecting the eyeglass lenses and blocking a substantial portion of the ambient light from striking the eyeglass lenses.

Abstract: A focusing device for a binocular instrument can include a single focusing drive means provided between right and left ocular lenses so as to simutaneously move the right and left ocular lenses forward and backward in a direction of an optical axis to effect focusing. The focusing device also includes a pair of right and left guide holes formed in a body of the binocular instrument which extend from the ocular side to the portion of the binocular body accommodating Porro prisms or Porro mirrors. The guide holes extend in coaxial relation to respective ocular optical axes. A pair of right and left ocular tubes respectively support the ocular lenses and are received respectively in the guide holes so as to be slidable along the respective ocular optical axes. A connecting means connects each of the ocular tubes to the focusing drive means.