Total eclipse of the Sun
Staring at the Sun is not a good idea most of the time. But on occasion, you would be mad not to. On 11th August 1999 millions did just that, witnessing a total eclipse of the Sun as the moon passes directly between the Sun and the earth, casting its full shadow over the planet in daytime.
In doing so, only the corona of the Sun becomes visible – solar fronds, the result of storms above the surface of the sun, fringing the shadow of the moon, bringing a temporary sense of darkness to the world. For most, it was an exciting diversion; it was astronomy invading everyday life – just like Sir Patrick Moore used to do with the sky at night. People who had hitherto not known their Dog Star from their North Star were donning protective glasses given free with newspapers and looking skyward.
Such is the power of the Sun, one single exposure is not sufficient to capture the celestial magic of the total eclipse’s corona. Speaking to BBCOnline, NASA scientist Dr Fred Espenak described how a computer was needed to create a composite image at a number of exposures was needed to go part of the way to seeing what the human eye could see.
He said: “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.”
The total eclipse of the Sun of August 1999 brought many scientific phenomena to the fore. For scientists this presented a rare opportunity to observe, measure and understand the Sun’s influence over the Earth’s atmosphere. The event, predicted years in advance, is the closest that scientists can get to a controlled experiment on the sun and its energy, and affords them a better chance of understanding the secrets of the Earth’s atmosphere.