日食共有三种，即：日偏食、日环食和日全食。月球遮住太阳的一部分叫日偏食。月球只遮住太阳的中心部分，在太阳周围还露出一圈日面，好象一个光环似的叫日环食。太阳被完全遮住的叫日全食。这三种不同的日食的发生跟太阳、月球和地球三者的相互变化着的位置有关，并且也决定于月球与地球之间的距离变化。

　　月球比太阳小得多，它的直径大约是太阳直径的四百分之一，而月球与地球间距离也差不多是太阳与地球间距离的四百分之一，所以从地球上看，月亮与太阳的圆面大小差不多相等，因而能把遮住而发生日食。

　　地球公转和月球公转轨道都是椭圆，不论是太阳与地球间距离，还是月球与地球间距离，并不是固定不变的，而有时比较远，有时又比较近，因此月球本影的长短也不一样，月球本影最长时有379660公里，最短时为367000 公里，而地球与月球之间的距离最近时为356700公里，最远时达406700公里。如果某个时刻月球本影比地球与月球之间的距离大，地球上被月球本影扫过的地带就可以看到日全食。如果月球本影比地球与月球之间的距离小，月球本影的尖端到不了地球的表面，那么在影尖延长出来的小影锥（叫伪本影）扫过的地带可以看到日环食。被月球半影扫过的地带均可以看到日偏食，在偏食区内离全食区越近，偏食的程度就越大。月球本影和半影没有扫过的地方，根本看不见日食。

　　　　The type of solar eclipse

　　　　A total solar eclipse of three, namely: the partial eclipse, on the Environment and Food and Riquan Shi. The moon covered the sun is part of the partial eclipse. Moon only cover the central part of the sun, the sun also exposed a circle around the face, seems like a halo called on the Environment and Food. The sun is completely covered Riquan Shi. This three different solar eclipse occurred with the sun, moon and Earth all three of the mutual changes of position, and also decided on the Moon and the distance between the Earth changes.

　　　　The moon was much smaller than the sun, it is about the diameter of the sun's diameter 1/400, and the distance between the Earth and the Moon also is almost the distance between the Sun and the Earth's 1/400, from the earth, the moon and Sun's round face almost the same size, which can cover and a solar eclipse.

　　　　Earth to the Moon and are elliptical orbit to the public, whether the distance between the Sun and Earth, or the distance between the Earth and the moon, is not fixed, and sometimes distant, sometimes relatively recent and therefore the length of the moon Benying not the same , The longest time the moon Benying 379,660 km, 367,000 km for the shortest possible time, the Earth and the moon and the distance between the last at 356,700 km, the farthest reaches up to 406,700 km. If a moment of Earth and the Moon Benying than the distance between the moon, the moon on Earth was Benying sweep of the area will be able to see Riquan Shi. If the moon Benying Earth and the moon than the distance between the small, cutting-edge to the moon Benying not the earth's surface, then in the video pointed out the extension of small shadow cone (called pseudo-Benying) sweep of the area can be seen on the Environment and Food . The sweep was the moon penumbral zone can see the partial eclipse, the partial eclipse in the region-wide water from the area near, the greater the extent of the partial eclipse. Penumbral lunar Benying and did not sweep the place, simply can not see the solar eclipse.

　　　　以下是本世纪（1901-1999）发生全世界范围内日食的次数：

　　　　种类 次数

　　　　日偏食 78

　　　　日环食 73

　　　　日全食 71

　　　　混合食 6

　　　　总计 228

　　　　Following is the century (1901-1999) in the world within the framework of the number of solar eclipse:

　　　　The number of species

　　　　78, the partial eclipse

　　　　On the Environment and Food 73

　　　　Riquan Si 71

　　　　Mixed Fresh 6

　　　　Total 228