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    Re: Any reliable computation of terrestrial refraction?
    From: Antoine Couëtte
    Date: 2024 Jun 6, 05:42 -0700

    Dear All,

    Further to my last contribution on this subject, I think that there is an adequate solution - at least adequate under normal atmospheric conditions - to my early query : Any available existing available theory to pre-compute refraction between 2 nearby points knowing Positions and Altitudes of departing and arrival points ?

    The attachment gives 2 solid references from which a simple computation method is derived and which is reliable, at least under "standard" atmospheric conditions.

    Such numerical approximation can be summarized as follows:

    At low altitudes, the vertical elevation between 2 [nearly] horizontal points at a finite distance is equal to about 8% of their distance in NM.

    As shown in the enclosure, what is amazing - to me at least - is that when we subtract such 8% from the unrefracted sea horizon Dip - Dip’ Unrefracted = 1,925 √h m  we obtain exactly the refracted horizon Dip - Dip’ Refracted = 1,771 √h m - "Official" [worldwide] figure for standard atmosphere.

    No age to keep learning !

    Enjoy !


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