Abstract: Optical system for directing an auxiliary image towards an observer so as to be superimposed on to a main image. The optical system comprises a pentagonal prism having a first surface for intercepting the auxiliary image and directing an auxiliary image beam toward an opposing second surface so as to be internally reflected by the second surface towards a third surface so as to be internally reflected by the third surface and propagated out of the pentagonal prism through a fourth surface opposite the third surface towards the observer. At least one of the surfaces of the pentagonal prism is aspeheric and a directing optics constituted by a wedge proximate and external to the third surface directs a main image beam derived from the main image through the third surface into the pentagonal prism and out of the fourth surface thereof towards the observer.

Abstract: An optical combiner for use with an optical eyepiece which is adjusted for viewing a first image, and which injects a non-collimated light beam from a second image substantially along an optical axis of the eyepiece so as to present a combined image to an observer. The combiner comprises a beam splitter for inserting into the eyepiece and having an entry aperture for intercepting the non-collimated light beam and directing a portion thereof outside the eyepiece so as to superimpose the second image on the first image.

Abstract: An adapter for an optical eyepiece for propagating a non-collimated light beam from an object along an optical axis of the eyepiece so as to present an image to an observer, the adapter comprising a beam splitter for inserting into the eyepiece so as to intercept the light beam and direct a portion thereof outside the eyepiece through an exit aperture of the beam splitter without substantially changing the image to the observer. The adapter is particularly useful for extracting a portion of an image from an eyepiece having restricted access in a night vision goggles thus permitting an external scene to be recorded simultaneous with its being viewed by the observer.