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There is no doubt that the Sun is immensely important to us here on Earth. Without it there would be no light and no life. Hanging over us a million times bigger than the Earth, the Sun dominatesour lives, inspiring our ideas in fields as diverse as science, art and religion. However, in cosmic terms, the Sun is a fairly average star. It is middle-aged, medium sized and has a mediocre surface temperature of 6000ºC. But it is this middle-of-the-road character that makes the Sun our ideal companion. If the Sun was a hot blue star, then the Earth would have been fried long ago. And if the Sun were a cool red giant, then our current location would place the Earth right inside it. The Sun, like all stars, is a huge atomic factory, fusing hydrogen atoms together to form helium. Amazingly, the Sun burns its fuel at the rate of 4 million tonnes per second. But even at this pace, it will not start running out of supplies for 5 billion years. Although the Sun looks very uniform to us here on Earth, probes such as TRACE and SOHO have photographed the Sun directly, showing it to be a seething mass of chaotic energy. The root of this turbulence is the constant battle between the Sun's powerful magnetic field and its spinning otion.The Sun has a magnetic field and a North and South pole, just like the Earth. But unlike the Earth, the Sun doesn't rotate as a solid body. The equator revolves faster than the poles and so, as the Sun spins round, its magnetic field lines wind up like a spring. Eventually they reach breaking point and burst, resulting in the total reversal of the Sun's magnetic field. So the poles swap round periodically in a cycle lasting 22 years. This is actually happening to the Sun at this very moment as it reaches the climax of its current cycle in 2001. This enormous upheaval is the cause of the Sun's uneven features, such as sunspots and prominences. Sunspots are regions of strong magnetic force that spread across the Sun periodically. Prominences are huge sprays, surges or loops of stellar material that shoot above the surface. These are areas where the churning magnetic field lines have burst out, dragging layers of burning gas with them. Sometimes these cause solar flares, releasing particles into space that can affect man-made satellites around Earth. |
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ECLIPSE COLLECTION Solar eclipses are easy to photograph, insuring that you protect your eyes. A heavy tripod is recommended to stabilise a camera with a long lens. Lenses of long focal length will produce larger images of the Sun than smaller lenses. Some experienced eclipse photographers recommend using a 2x tele-converter with a 500mm lens to gain a focal length of 1000mm. But, anything shorter than 400mm will fail to show the corona and other phenomena. However, too long a lens reduces the already low light levels present during a solar eclipse.
Don't try photographing the partial phases before and after totality without
using special
African Eclipse 2001 |
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