The present invention is a lightweight night vision device (NVD) sealed from environmental conditions, shielded from electromagnetic interference (EMI), and having mechanisms for easy adjustment and fixation of collimation and interpupillary distance. The NVD monocular housing is integrated with the eyepiece, image intensifier tube module, and objective, allowing collimation to be fixed via an optical alignment of the monocular housing to its eyepiece, tube module, and objective. Certain components from existing NVDs may be reused in assembling the present invention to provide cost savings.