Total solar eclipse of 11th August 1999. Solar eclipses occur when the Moon passes between the Earth and the Sun. The solar corona (white) is seen during eclipses. This is the outer layer of the Sun, comprising rarefied gases at extremely high temperatures. The corona is usually hidden by the glare from the surface of the Sun. At this time, the Sun was near its maximum activity during its 11-year solar activity cycle. Because of this, the corona is seen spaced evenly around the Sun. During a solar minimum the magnetic poles of the Sun are more powerful, and the corona is weak at the poles and stronger at the centre. Photographed from Turkey.