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    Re: Refraction:Which formula for Hei ghts below 15°
    From: David Iwancio
    Date: 2022 May 18, 21:00 -0700

    Just as an aside, for adding predicted refraction to a pre-computed altitude, I ended up with:

    cot[Hc + 8.72/(Hc+4.36)]

    All I did was fit the curve to the NA refraction tables through two points:  where Hc equals 0 and where the expression "A/(Hc+B)" equalled 1.

       
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