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    Re: Refraction near the Horizon ? Observation vs. Calculation
    From: Marcel Tschudin
    Date: 2013 Apr 9, 00:21 +0300

    Thanks to all of you for the information regarding the N.A. The idea
    is to start by comparing my observations with results corresponding to
    the N.A. and then show whether better agreeing results can be found or
    On Mon, Apr 8, 2013 at 11:10 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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