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Eclipses -The Earth, the Moon and the Sun Dancing in The Sky

Under very special circumstances the dances of the Earth around the Sun and the Moon around our Earth make a special play for us. One of these plays are eclipses. Eclipses happen when a celestial body obscures or blocks the light of another one. For the case of the Sun-Earth-Moon system, when the moon blocks the view of the Sun we have a solar eclipse.

A lunar eclipse occurs when the shadow of the Earth obscures the surface of the Moon. For the lunar eclipses, we can have a partial Lunar Eclipse when the shadow of the Earth obscures part of the Moon. A total lunar eclipse happens when the shadow of the Earth manages to cover the entire surface of the Moon. For the case of a Solar Eclipse, some details about the sizes of the objects and their orbits need to be discussed. By pure coincidence, the sizes of the Moon and the Sun are related to a factor of about 400 and it turns out that the distances of the Moon and the Sun as viewed from Earth are related to a factor of 400 also! 

That means that the relative sizes of the two objects in the sky is the same and both, the Moon and the Sun cover about 0.5° of the sky. That is why the Moon can cover the entire disk of the Sun during a solar eclipse. On the other hand, it has to be taken into account that the orbits of the Earth around the Sun, and the Moon around the Earth are not perfect circles but instead they are ellipses. That means that sometimes the Moon is closer to the Earth while in other occasions the Moon is a bit further away from the Earth. Likewise the Earth can be closer or further away from the Sun. If the alignment is adequate and the distances are right, the Moon can cover the entire disk of the Sun, and then we have a total solar eclipse. However, that is not always the case, therefore, when the Moon can not cover the entire disk of the Sun, we have a partial solar eclipse. 

Under very special circumstances, when the Moon is far from the Earth, the disk of the Moon can not cover the entire disk of the Sun, leaving a ring of Sun and this is what we call an Annular Solar Eclipse. Tomorrow we will witness the clockwork precision of the movements of the Earth and the Moon, and we will witness a partial solar eclipse from our ship's position. However tomorrow's eclipse is also an annular solar eclipse for a region of our planet located about 800 miles north from our current position.

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