What is an annular eclipse and how do they occur?

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BRIDGEPORT, W. Va. (WDTV) - An annular eclipse is also called a 'ring of fire' eclipse. This is when the moon gets directly between the Earth and the sun but doesn't completely cover it. The outside of the sun is still visible as a ring around the moon.

A total eclipse is when the moon completely covers the sun. This leaves the sun's outer atmosphere, 'corona' visible. This is usually not visible due to the brightness of the sun.

The main factor which causes a total eclipse versus and annular eclipse is the distance between the moon and the Earth. This is not constant. The moon orbits the earth in an elliptical shape. This looks like an elongated circle. Longer at the ends and shorter at the sides.

A total eclipse happens when the moon gets between the Earth and the sun, intersecting the plane of the Earth's orbit around the sun (the area the Earth sweeps out as it revolves around the sun in a year). For the moon to completely cover the sun, it needs to be close to the Earth. Therefore, it is bigger in the sky, totally covering the sun.

For an annular eclipse, the moon is farther away from the Earth. It appears smaller in the sky, and only covers up most of the sun. A ring of the sun appears outside the moon since it's apparent size can't completely cover the sun.