Subj : Daily APOD Report
To   : All
From : Alan Ianson
Date : Tue Mar 28 2023 00:17:50

                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                2023 March 28
   A distant sunset is seen between an orange sky and dark clouds. A close
     look at the Sun shows it is topped with several green strips, each
    known as a green flash. Please see the explanation for more detailed
                                information.

                        A Multiple Green Flash Sunset
   Image Credit & Copyright: T. Slovinsk+' & P. Hor+ílek (IoP Opava); CTIO,
                             NOIRLab, NSF, AURA

   Explanation: Yes, but can your green flash do this? A green flash at
   sunset is a rare event that many Sun watchers pride themselves on
   having seen.  Once thought to be a myth, a green flash is now
   understood to occur when the Earth's atmosphere acts like both a prism
   and a lens. Different atmospheric layers create altitude-variable
   refraction that takes light from the top of the Sun and disperses its
   colors, creates two images, and magnifies it in just the right way to
   make a thin sliver appear green just before it disappears. Pictured,
   though, is an even more unusual sunset. From the high-altitude Cerro
   Tololo Inter-American Observatory in Chile one day last April, the Sun
   was captured setting beyond an atmosphere with multiple distinct
   thermal layers, creating several  mock images of the Sun.  This time
   and from this location, many of those layers produced a green flash
   simultaneously. Just seconds after this multiple-green-flash event was
   caught by two well-surprised astrophotographers, the Sun set below the
   clouds.

                    Tomorrow's picture: dolphin vs cloud
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

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