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    Re: Lunar Distances with Alex's SNO-T
    From: Alexandre Eremenko
    Date: 2006 Oct 31, 08:59 -0500

    I see, this sounds reasonable.
    But then I need a barometer, or to correct
    the pressure from the Weather channel for
    my altitude, because,
    if I understand correctly, the pressure broadcast
    for the weather prediction is reduced to the sea level.
    On Tue, 31 Oct 2006, Fred Hebard wrote:
    > Alex,
    > Use the actual pressure.  That is the determinant for the refraction
    > correction.  The elevation above sea level has an insignificant
    > effect on parallax, when you consider that the radius of the earth is
    > about 3400 nautical miles, but significantly reduces refraction via
    > the effect on barometric pressure.
    > Fred
    > On Oct 31, 2006, at 8:27 AM, Alexandre E Eremenko wrote:
    > > Related question: the barometric pressure in the refraction formula.
    > > Should I use the actual pressure at my observation site,
    > > or should I "reduce it to the sea level"?
    > > The actual pressure at my site reflects not only the deviation
    > > from the standard atmosphere but also my altitude over the sea level.
    > >
    > > Alex
    > >
    > >
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