The improvement comprises {TAIL ~ means} for locating a target with respect to the generation subsystem and means for locating {HEAD ~ an aiming point} in the image display subsystem with respect to the image generation subsystem 
The improvement comprises { TAIL ~ means } for locating a target with respect to the generation subsystem and means for locating { HEAD ~ an aiming point } in the image display subsystem with respect to the image generation subsystem
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH