我們都知道，月球繞著地球跑，地球又帶著月球繞太陽跑，所以就會發生月球跑到地球、太陽中間的情形。當這三個天體跑到同一條直線上，或接近一直線時，月球剛好擋住了太陽，於是就產生了日蝕。
而另一種情形是，它們三個又跑到呈一直線，但是這次是地球在太陽和月球的中間，也就是地球擋住了太陽，於是就出現了月蝕。
日蝕發生的時候，會因為觀測者所在的地點不同，而會看到不一樣的現象。有人在地球被月球本影所籠罩的地方，看到的就是日全蝕；若是在太陽只被月球遮住一部份的地方，看到的就是日偏蝕。另外，如果月亮的陰影不能達到地面，那在被月影延長線所包圍的區域內，還是可以看到太陽的邊緣，就成了日環蝕。
而月蝕發生時，月亮全部被地球遮住，就是月全蝕；只遮住一部分，則是月偏蝕了。
Eclipse and the occurrence of a lunar eclipse with the Earth's revolution, rotation, and the moon.
We all know that the moon cover the globe, the Earth has run with the moon around the sun, the moon will occur so went to the Earth, the sun among the cases. When the three went to the same object in a straight line, or close to a straight line, the moon is just blocking the sun, and thus a solar eclipse.
The other scenario is that they are three then went to a straight line, but this is the earth in the middle of the sun and moon, that is the earth blocking the sun, so it was a lunar eclipse.
Eclipse occurs when the observer because of their location is different and will see a different phenomenon. Some people in the earth is a place shrouded moon eclipse, total eclipse is seen; if the moon covered the sun was only a part of the place, to see that the partial eclipse. In addition, if the moon's shadow can not reach the ground, then extend the line in the shadow of the moon was surrounded by the area, or you can see the edge of the sun, it becomes an annular eclipse.
