Clip-on night vision device

A night viewer ( 10 ) is adaptable to generate an enhanced image suitable for viewing through an optical scope ( 16 ). An input end ( 18 ) of the viewer ( 10 ) receives the image to be enhanced through an objective lens ( 20 ). An image enhancing unit ( 22 ) enhances the image. The enhanced image is optically transmitted from a display ( 28 ) to the ocular lens ( 24 ) of the scope ( 16 ). The display ( 28 ) is operably connected with the image enhancing unit ( 22 ) to display the enhanced image. A Risley prism ( 30 ) located in an image path ( 32 ) is used to controllably adjust and to maintain boresight alignment ( 36 ).