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    Re: Corrections for refraction in deserts
    From: Geoffrey Kolbe
    Date: 2006 Mar 7, 06:07 +0000

    Thanks for that Frank. That is most useful.
    
    It will be interesting to plot Ho error against Hc for my sightings when I
    get back and see if any significant anomalous dispersion comes out of the data.
    
    Geoffrey Kolbe
    
    
    >Here's a refraction table prepared for ocean conditions for every half
    >degree of altitude from 0 to 5 degrees above the  horizon:
    >33.8'
    >28.3
    >24.1
    >20.8
    >18.2
    >16.1
    >14.3
    >12.9
    >11.7
    >10.7
    >9.8
    >And  here's a similar refraction table for desert  conditions:
    >32.4'
    >27.5
    >23.6
    >20.5
    >18.0
    >15.9
    >14.3
    >12.9
    >11.7
    >10.7
    >9.8
    >As  you can see, they match for altitudes of 3 degrees and higher. Both
    >tables are  for standard temperature and pressure at sea level so you
    >still would
    >need to  apply corrections for non-standard T and P and for altitude above sea
    >level.
    >
    >Of course, tables like these are only right when the actual conditions  match
    >the input conditions. It's easy to imagine conditions in the desert, for
    >example, right after sunrise, when the temperature distribution would not
    >match
    >the assumptions above at all.
    >
    >-FER
    >42.0N 87.7W, or 41.4N  72.1W.
    >www.HistoricalAtlas.com/lunars
    
    
    

       
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