Quote:
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Originally Posted by Celestial Mechanic
Quote:
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Originally Posted by AGN Fuel
[Snip!]The Earth's atmosphere refracts sunlight approximately 35 arcseconds when the sun appears to be on the horizon, but the disc of the sun itself is around 30 arcseconds in diameter. This means that when the sun is physically just below the horizon, refraction still allows us to see it.[Snip!]
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Actually the figure is more like 35 arcminutes for the refraction, but it varies depending on meteorological conditions. For calculating sunrises and sunsets the standard procedure is to take the standard refraction to be 34 arcminutes and the radius of the Sun to be 16 arcminutes so that sunrise/sunset is the moment when the center of the Sun's disk is 90 degrees 50 minutes from the zenith. |
#-o Dyslexic fingers! 35 arcseconds....... #-o
I knew what I meant, anyhow!  ops:
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