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    Re: Extremely poor conditions??
    From: Alexandre Eremenko
    Date: 2012 Mar 20, 11:55 -0400

    Well,
    Then it should be probably better called "anomalous dip".
    Dip with the opposite sign of the normal dip.
    If this is what has happened, and the refraction bended rays
    in the usual direction then this anomalous dip must have been
    more than 10' in our observations!
    
    It is pity we did not suspect anything like this.
    We could probably observe at the sea level, and with art horizon,
    we could time the moment of sunset etc.
    
    I still have to dig the old archives on the anomalous refraction.
    I even sort of remember reading a paper of Wollaston in
    the Royal Soc. Proc. where he investigated this for the first time,
    if I remember correctly.
    
    Alex.
    
    On Tue, 20 Mar 2012, Gary LaPook wrote:
    
    >
    > But abnormal refraction also raises the horizon. Fata morganas and other 
    mirages are caused by the refraction raising objects at ground level, 
    observed at essentially zero altitudes and the horizon is also raised. Your 
    observations of the sun may also have been raised but not as much as the 
    horizon since they were higher to begin with.
    >
    > gl
    >
    > --- On Tue, 3/20/12, Alexandre E Eremenko  wrote:
    >
    > From: Alexandre E Eremenko 
    > Subject: [NavList] Re: Extremely poor conditions??
    > To: NavList@fer3.com
    > Date: Tuesday, March 20, 2012, 6:53 AM
    >
    >
    > John,
    >
    >> I've heard of a report of some very impressive looming over Lake Michigan
    >> in the spring.   I recall that people in a town in Michigan could see the
    >> lights of Milwaukee one night - 80 miles away and well over the geographic
    >> horizon.
    >
    > But this is "normal refraction", I mean very large, but "in the normal 
    direction": The light ray is curved in the same direction as the
    > Earth surface. This sort of refraction would require NEGATIVE
    > correction to compensate it. In our case, the refraction had to be
    > in the opposite direction: the ray had to be curved on the opposite
    > direction to the Earth surface.
    >
    > This means that the remote toll bioldings whose tops are normally visible
    > would be unvisible in these conditions.
    >
    > Alex.
    >
    >
    >
    >
    >
    >
    >
    >
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=118421
    >
    >
    >
    
    
    

       
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