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    Re: refraction
    From: Guy Schwartz
    Date: 2007 Jan 4, 19:31 -0800

    Lets take the sun for example, how would one know if they were viewing it
    with or without refraction to start the analysis?
    ----- Original Message -----
    From: "Lu Abel" 
    Sent: Thursday, January 04, 2007 7:11 PM
    Subject: [NavList 1977] Re: refraction
    > Not much different than measuring bending of the stick, Guy, except with a
    > bit of patience required.
    > If I track the rising or setting of a body, I should see a uniform rate of
    > motion in the sky as long as refraction is insignificant.  Once it becomes
    > significant, however, the rate should change.
    > I could, for example, calculate the expected time a body would disappear
    > below the horizon based on its motion through the sky.  But I would
    > observe it to set later.  The time of observed setting would lead me to a
    > value for refraction, ie, the amount the body is below the horizon and
    > therefore the amount of refraction.
    > Measurement of factors such a pressure, humidity, and temperature could
    > then be used to refine the parameters.
    > Lu Abel
    > Guy Schwartz wrote:
    >> Inserting a 4 foot stick half way into a big tank of water at a 45 degree
    >> angle, the refraction can be measured or closely approximated.
    >> How were the refraction adjustments initially calculated for the
    >> atmosphere?
    >> What was the methodology used? I don't think it was as easy as the stick
    >> in the water method?
    >> Thank you.
    >> Guy
    >> >
    > >
    > --
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    > 1:34 PM
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