Abstract: A Midwave FLIR imaging optical apparatus has both a narrow and wide field of view. The imaging optical apparatus has a See Spot mode of operation, where a laser designator spot image is superimposed on the FLIR image in the narrow field of view. A laser rangefinder receiver path is also provided. A shared aperture collects incident radiation, which after manipulation by a plurality of optically significant surfaces, projects radiation to a detector. The imaging optical system is lightweight and compact and efficiently transmits FLIR energy and a narrow band of laser energy so that a signal due to a source outside the pass bands of interest (including solar energy) will not adversely effect operation of the imaging optical apparatus.