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    Re: Navigator's Vision,Day or Night.
    From: Jeremy C
    Date: 2009 Oct 7, 10:26 EDT
    This also works very well when trying to see running lights at a fair distance.  My use of this technique allows me to pick up ships at 15-20 nm from the bridge well before most of the other watch standers can see the ship.  Generally in good visibility, I can see the running lights soon after they pop over the horizon.
     
    Jeremy
     
    In a message dated 10/5/2009 2:21:55 P.M. Eastern Daylight Time, byronink@netzero.com writes:


    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.


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