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    Re: Was Bowditch Table 15, now confused
    From: Bill B
    Date: 2005 Jan 28, 17:34 -0500

    > Perhaps a clearer way to put it is that the Sensible Horizon
    > is perpendicular to the vertical.  As it happens, measurements
    > using a pool of oil or mercury are relative to the Sensible
    > Horizon.
    
    Not clear how to interpret that.
    
    Is the sensible horizon is a plane perpendicular to the vertical (line
    through center of the Earth and viewer), AT THE VIEWER'S HEIGHT OF EYE, as I
    understand Jim's drawing?
    
    General instructions for a pan of oil etc. instruct the user to place it on
    the ground.  No dip correction.  If it relates to the sensible horizon and
    my understanding of the definition is true, then dip correction would be
    required if the pan were placed on a stool?  That doesn't seem right to me.
    
    I do clearly understand I am deeply confused.
    
    Bill
    
    
    

       
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