Care of Binoculars Binoculars  are  fairly  delicate  instruments;  they cannot stand much knocking about. Therefore, keep them on a short strap when wearing them to prevent their banging against solid objects.   Always   keep the strap around your neck. Never hold binoculars over the side of the ship without the strap being around your neck. Many pairs of binoculars have been lost over the side in this manner. Keep the lenses dry; otherwise, you will not be able to see properly. Don’t let them become overheated; the cement around the lenses might melt. Above  all,  keep  them  clean.  You  must  be  careful, however, not to damage the lenses when cleaning them. First, blow off loose dust; then breathe on the lenses (except in freezing weather) and gently clean them with lens paper. Rags, plain paper, handkerchiefs, or your sleeve or shirttail should not be used, as they might scratch the lens. You can usually get a supply of lens paper from the QMOW. NIGHT VISION Have you ever walked from a lighted theater lobby into the darkened theater? You would almost be blind for a few minutes. As your eyes become accustomed to the weak light, your vision gradually improves. The same  situation  exists  when  you  go  on  night  watch directly from a lighted compartment. After 10 minutes, you can see fairly well. After 30 minutes, you reach your best night vision. This improvement of vision in dim light is called  dark adaptation. Specially designed red goggles are provided for you to use before you go on night lookout duty. These goggles  prepare  your  eyes  for  darkness  without affecting your ability to play games, write letters, or read before going on watch. You should wear them without interruption for at least half an hour before going on watch. Even then, it will still take you at least 5 minutes more in darkness to develop your best night vision. After your eyes are dark adapted, you must learn to use your  night eyes. In the daytime, you should look directly at an object to see it best. In the dark, you need to look above, below, or to one side of an object to see it. This is called  off-center vision. At night, it’s also easier to  locate  a  moving  object  than  one  standing  still. Because most objects on or in the water have a relatively slow speed, we move our eyes instead, and the effect is nearly as good. Therefore, while scanning at night, lookouts move their eyes in slow sweeps across the area instead of stopping the eyes to search a section at a time. Your  ship  may  be  equipped  with  night  vision equipment. Before standing watch, be sure you are trained in operating the night vision equipment assigned to your ship. SCANNING PROCEDURES A well-trained lookout will see much more than a “green” hand would see. In good weather, lookouts can easily spot planes with the naked eye at 15 miles. With binoculars and in unusually clear weather, lookouts have  detected  planes  at  50  miles.  At  night,  skilled lookouts will detect objects that the untrained lookout would never suspect were there. The lookout’s technique of eye search is called scanning, which is a step-by-step method of looking. It is the only efficient and sure way of doing the job. Scanning does not come naturally. You must learn to scan through practice. In the daytime, your eyes must stop on an object to see it. Try moving your eyes around the room or across the water rapidly. Note that as long as your eyes are in motion, you see almost nothing. Allow your eyes to move in short steps from object to object. Now you can really see what is there. Figure 3-8 shows how you should search along the horizon. (You also must cover the surface between your ship and the horizon.) Search your sector in 5° steps, pausing between steps for approximately 5 seconds to scan the field of view. At the end of your sector, lower the glasses and rest your eyes for a few seconds; then search back across the sector with the naked eye. Lookouts also search from the horizon to the zenith (overhead), using binoculars only to identify a contact. Move your eyes in quick steps (about 5°) across your 3-17 Student Notes: Figure 3-8.—Scanning using the step-by-step method.