In this spectacular view of the Earth, the northern auroral oval is seen as a "crown" at the top of
the image. A coastline superposed on the image shows that the aurora is positioned just north of the Great
Lakes. The extended region of light in the center and bottom of the image is the glow from the sun's
illumination of Earth's upper atmosphere. The filter for this image passes ultraviolet emissions that are
not directly visible to the human eye. The intensities of this light from atomic oxygen in Earth's atmosphere
at altitudes in the range of about 100 to 500 km are color-coded in the image with dark red as the lowest
intensities and whitish yellow as the brightest intensities. The picture was taken at 00:37 UT on March 25,
1996 with the Earth Camera, one of three cameras in the Visible Imaging System, which was designed and
constructed at The University of Iowa. Advances in technology for the construction of these cameras allow
images of the auroral oval to be acquired for the sunlit atmosphere with unprecedented clarity, as amply
demonstrated by this picture of a complete auroral oval that extends into the sunlit atmosphere. This image
was acquired while the spacecraft was at an altitude of 25,740 km. The geographic latitude and longitude of
its position was 57.7° and 201.4°, respectively.
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