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    Re: Sextant accuracy with short distance to horizon
    From: Steven Wepster
    Date: 2001 Jun 22, 2:13 AM

    Dear Dan and others,
    
    In my opinion you have hit a problem that is specific to astro on
    yachts: the very small height of eye. The problem is not so much that
    it makes the horizon nearby. The normal dip table should be sufficient
    as long as it lists your height of eye. I don't know for shure what
    Peter and  Russell meant by 'dip short' tables: my 1981 Bowditch
    Vol.II has a different table 14, but it has a table 22 'Dip of the Sea
    Short of the Horizon'. This table gives the dip of objects _in front
    of_ the horizon, so it should not be used for a normal altitude above
    the horizon.
    
    More important: because your eyes are so low above the sea, it is most
    of the time just plainly impossible to _see_ the horizon. The waves
    get in between. When it is almost dead calm, there's no problem (but
    it's not fun sailing then). You're lucky when the swell is running
    high and regular, because then you can take a shot when you're at the
    top.
    
    This raises another question: what is your height of eye at the top of
    a wave? Do you have to add the wave height to your height above the
    waterline of the vessel?
    
    In my opinion, the anser to that question is 'no'. I assume that waves
    of appoximately the same height make up the horizon.
    
    _Steven
    

       
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