Eclipse provides unique solar image
Source: BBC News Online Science Editor Dr David Whitehouse
12th Aug 1999
For the millions who saw it, August's total solar eclipse was an unforgettable experience that cannot be adequately captured in words or on film.
Only during a total eclipse can the Sun's faint outer atmosphere called the corona be seen. During totality, prominences and streamers can be seen in this thin gas which is at a temperature of many millions of degrees. Now, one of the world's leading experts on eclipses has tried to capture on film what the eye can see of the corona during the fleeting moments of totality.
"The solar corona exhibits a huge range in brightness which cannot be captured in any single photographic exposure," Dr Fred Espenak of NASA told BBC News Online.
Short exposures show the bright inner corona and prominences, while long exposures reveal faint details in equatorial streamers and polar brushes. "Fortunately, the computer can be used to combine a series of images taken at different exposures into a single composite image which more closely resembles the corona's appearance as seen by the human eye," said Dr Espenak.
He photographed August's total solar eclipse from Lake Hazar in Turkey. After processing his negatives and scanning them into a computer, he made a composite image of the corona using 22 separate exposures. The image comes much closer than conventional photography does to showing how the corona actually appears to the eye.
"Of course," adds Dr Espenak, "nothing can replace the experience of seeing a total eclipse for yourself!"
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