Illustration taken from the 'Illustrated London News'. Drawn by J Grantley Tingle, the corona and north/south axis of the moon are indicated. The corona is the very hot outer part of the solar atmosphere which consists of highly ionised gas superheated to temperatures in exces of 1 million degrees Celsius. It can normally only be seen visually during a total solar eclipse, when it appears as a halo or cloud of pearly white light. Solar eclipses have always inspired fascination, awe, and indeed terror in ancient times. In the 19th century, expeditions were dispatched around the world to make scientific observations of eclipses, and today a dedicated band of 'eclipse tourists' is prepared to travel to almost any location where the phenomena can be seen.
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