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    Fwd: Re: Sextant accuracy with short distance to horizon
    From: Dale Tilson
    Date: 2001 Jun 26, 1:50 PM

    Re: the Aussie using his fence for a horizon, several people wrote:
    
    > >> That's interesting. But surely one must make an allowance for the fact
    > >> that the fence is not at the same altitude as the horizon.
    > >
    > >I can't remember that much about the post, but I THINK he had some kind
    > of HE
    > >correction for his eye above the fence line.
    > >
    >He would need extremely accurate survey data if there was
    >any meaning to be had. He would have to know the relative
    >height of the fence and his eye, as well as the distance to
    >the fence.
    
    OK, guys, I'm new at this so somebody help me out.
    
    I thought the "dip" correction was necessary because the horizon isn't
    level with your height of eye.  Aren't we actually trying to measure
    altitude above a line horizontal with the line-of-sight?  If so, our Aussie
    friend would only need to find a perch so that his eye was level with the
    fenceline.
    
    If not, somebody straighten me out quick, because I was gonna set up an
    observation post in the back yard based on that premise.
    
    Thanks,
    
    Dale
    

       
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