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    Navigator's Vision,Day or Night.
    From: Byron Franklin
    Date: 2009 Oct 5, 09:34 -0700

     Navigator's vision at day and night.
    The way you use your eyes at night is different from the way you use them 
    during the day. With normal day vision, you train your eyes to look directly 
    at the target. If you catch something out of the corner of your eye, you 
    automatically move your eyes to center on the target. Once you have done so, 
    you can see the target clearly in color, and detail. In the dark, however, 
    instead of directing your vision at the area you desire to see, you must 
    learn to use off-center vision for a very dim light or star.  The first step 
    in training yourself in night vision is finding a location free of normal 
    white city lights,   Perhaps your backyard or better at sea. Wait until your 
    eyes have adapted to the dark; this can take about 15 to 20 minutes. At this 
    point the sky is black, some stars are bright, or some dim and you are aware 
    of your surroundings. Your eyes are accustomed to the dark. If you need a 
    light to read/write or see a star finder (NAVLIST 9471) use a red dim light 
    only.  Look at the sky and find a bright star. Now slowly move your eyes 
    until you see, or think you see, the dimmest star out of the corner of your 
    eye. Look directly at the star. If it is a very dim star it will "disappear" 
    when you look at it and won't reappear until you move your eyes and "look" at 
    it using the off-center technique. It may well be fuzzy and lack color. But 
    you do see it. What is happening here is that you are seeing it with your 
    peripheral vision. Practice this off-center technique until you are 
    comfortable picking up even the dimmest star.  Binoculars can help make some 
    of the dimmer stars very bright. But other stars will disappear when you look 
    directly at them, even with binoculars. At sea at night, relax and move your 
    eyes slowly just a few degrees around the sky or the horizon. If you think 
    you see a light, use the off-center vision technique to isolate your target. 
    If the light is very faint and disappears, use a slow, off-center eye motion 
    to pick it up again. Then use your binoculars to pick up any color details. 
    Practice this off-center procedure until you are proficient in seeing things 
    at night. When you are in the darkness, only a trained eye can produce the 
    correct information quickly. In the day time when you want that good horizon 
    for a star or planet before dark thickens the horizon try the "Vertical 
    Sextant" NAVLIST of Sept 28. 
    NavList message boards: www.fer3.com/arc
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