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    Re: Longitude by Sunset
    From: Alexandre Eremenko
    Date: 2012 May 7, 12:24 -0400

    > I use this Bris with a digital camera.
    I understood. When I was contemplating this Mun/Moon rise/set method,
    I had one application in my mind, besides the pure theoretic interest:
    a lifeboat equipment:-)
    I was thinking of something like a map, magnetic compass,
    reduced almanac
    on plastic sheets,
    and a plastic sextant/quadrant. It is highly probable that at least one
    person in a lifeboat will have her wristwatch:-)
    Of course, no problem with adding a graduated "Bris sextant".
    But to equip a lifeboat with a digital camera and a computer...
    and batteries...
    But of course a digital camera is OK for a preliminary research:-)
    P.S. About 5-6 years ago I bought a 10 EU watch in an airport when my
    own watch stopped because I swam with it. I came home and put this 10 EU
    watch to a drawer. Today I was searching something in this drawer, and
    discovered that watch. It is 5 min ahead of time:-)
    So equipping a lifeboat with emergency watch is a good idea, but
    probably not with a chronometer:-)
      The reflected image isn't as bright as direct sunlight. At extremely low 
    altitudes near sunset no sunglasses are need when the Sun is an orange ball. 
    At higher altitudes with a different Bris then sun filters need to be added 
    to the device. On the camera there is some flexibility with the exposure 
    settings and in the electronic dark room.
    > Greg Rudzinski
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