NIGHT VISION GOGGLES

untrained eye. You must learn to scan through practice. Detailed information to help develop scanning skills is given in Basic Military Requirements. Maintenance To make sure the sights are always ready for operation, organizational maintenance personnel must perform a systematic inspection to discover and correct defects before they result in equipment failure. Scheduled maintenance is to be performed as described on current MRCs. If any part is defective or missing, other than those authorized for replacement or repair, requisition a replacement sight according to normal supply procedures. NIGHT VISION GOGGLES Night vision goggles, AN/PVS 5A, 5B, and 5C (fig. 2-18) provide improved night vision, using available light from the night sky. An auxiliary IR light source provides illumination for close-up work when ambient light is low. The goggles enable the user to observe from the air, as well as perform normal ground tasks such as reading, walking, and driving. The goggles are binoculars consisting of two identical monocular eyepieces mounted on an adjustable frame and may be moved sideways. Each monocular assembly consists of three primary subassemblies: objective lens assembly, image intensifier, and eyepiece lens assembly. The goggles are mounted in a cushioned face assembly, which is strapped on to the user. The goggles are approximately 5 inches high, 7 inches wide, 6 inches deep, and weigh 32 ounces without carrying case. The mechanical function of the goggles is to accommodate differences in the physical characteristics of individual users. This is done by adjusting the IPD, diopter setting, focus, and eye relief. The two monocular assemblies are mounted in the frame and may be moved laterally to coincide with individual user’s IPD. Lateral movement is performed by loosening the lever clamp, which releases tension from the guide assembly and permits each monocular eyepiece to slide on flanges of the tube housing. Each monocular eyepiece is moved manually to the desired IPD, and the lever clamp is tightened. Figure 2-18.—AN/PVS 5A, 5B, and 5C night vision goggles. To adjust the diopter setting, adjust each eyepiece by rotating the diopter adjust ring, which moves the eyepiece assembly nearer to or further from the user's 2-17