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    Re: Refraction near the Horizon ? Observation vs. Calculation
    From: Hewitt Schlereth
    Date: 2013 Apr 8, 13:23 -0700

    Yes, Marcel, they are on page 280 of the 2013 edition.
    
    Hewitt
    
    Sent from my iPad
    
    On Apr 8, 2013, at 1:10 PM, "Paul Hirose"  wrote:
    
    > Marcel Tschudin wrote:
    >> The refraction formula is indeed the one from Bennett in a form which
    >> provides the resutls in degrees. Bennett provided also a second
    >> formula for further improving the result of this first formula. Does
    >> your N.A. 1998 edition makes reference to it?
    > 
    > There's no reference to a more accurate formula.
    > 
    > The formula (including the corrections for pressure and temperature)
    > duplicates the almanac's high and low altitude refraction
    > tables within 0.1′ for the values I tried, assuming 10 C and 1010 mb. I
    > didn't test the almanac table A4 corrections for nonstandard conditions.
    > 
    >> Just in case these finding should one day be documented in a paper:
    >> How is the correct reference to this N.A. edition?
    > 
    > 1998 Nautical Almanac Commercial Edition, published jointly by Paradise
    > Cay Publication and Celestaire Inc., "Sight Reduction Procedures"
    > chapter, p. 280.
    > 
    > Does anyone have a newer almanac? Are the refraction and dip formulae
    > still included?
    > 
    > --
    > I filter out messages with attachments or HTML.
    > 
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=123455
    > 
    > 
    

       
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