Total solar eclipse 所谓"食"就是指一个天体被另一个天体或其黑影全部或部分掩遮的天文景象。日食主要有日全食、日偏食及日环食三种。日食发生的原理是地球上的局部地区被月影所遮盖而造成的。日食必发生在朔日，即农历的初一（朔）。这是因为只有在那一天，月亮才会出现在太阳与地球之间的连线上，这样才有可能使月球挡住太阳而形成日食。同样地，月食一定出现在望日，即农历十五。 大家可能会问，为什么不是每个月的初一都会有日食，还有，为什么不是每个月的十五都会有月食呢？这是因为除了上面的条件外，影响日食和月食出现的还有其他一些因素。我们把地球围绕太阳公转的轨道称为黄道，把月球围绕地球公转的轨道称为白道。黄道平面与白道平面不是相同的，它们之间平均有5°09′的夹角，并且随时发生变化。只有当月球运行到黄道和白道的升交点和降交点附近时，才会发生日食。 日食的种类 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。 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 日食的过程 日食的过程可分为五个阶段，而只有日全食才拥有全部过程，日偏食和日环食则没有食既和生光。初亏：太阳与月球第一次外切，太阳光球西面刚切入月球东面的时刻。食既：太阳与月球第一次内切，太阳光球刚完全被月球掩蔽的时刻。食甚：月球中心与太阳中心距离最小的时刻。生光：太阳与月球第二次内切，太阳光球刚从月球西面露出来的时刻。复圆：太阳与月球第二次外切，太阳光球刚完全离开月球背后的时刻。初亏、食既、生光和复圆又分别称为第一、第二、第三、第四接触。 翻译: The so-called "food" is a celestial body that was another celestial body or its Heiying Yanzhe all or part of the astronomical scene. Ri Quansi main solar eclipse, the partial eclipse and three on the Environment and Food. The principle is the solar eclipse occurred on Earth, some areas were covered by the shadow caused. Shuori solar eclipse will occur in that first day of the Lunar New Year (New Moon). This is because only in that day, the moon will appear in the Sun and the connection between the Earth, so will it be possible to block the sun and the moon formed the solar eclipse. Similarly, the eclipse will appear in Wangri that the Lunar New Year 15. You might ask, why is not the first day of each month will be a solar eclipse, why not the 15th of each month will be a penumbral eclipse » This is because in addition to the above conditions, the impact of the solar eclipse and the eclipse there are other factors. We the Earth around the sun to the track known as the ecliptic, the moon around the Earth to the track known as the White Road. Ecliptic plane and white plane, not the same, among them an average of 5 ° 09 'angle, and always changing. Only when the moon to run, and yellow or white Road intersection near the intersection and down only when a solar eclipse. 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. 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 The process of solar eclipse The process of the solar eclipse can be divided into five phases, but only to have the entire process of Riquan Shi, and the partial eclipse on the Environment and Food is not potable both light and Health. Early losses: the sun and the moon, the first cut, just west of the sun-Cut east of the moon moment. Fresh both: the sun and the moon within the first cut, sun-moon has just been totally masking the moment. Very fresh: the sun and the moon Centre Centre at the smallest distance. - Health: the sun and the moon, the second cut, sun-exposed just west of the moon moment. - Round: the sun and the moon, the second cut, sun-moon has just completely left behind the moment. Early losses, both fresh, light and health-circular also called the first, second, third, fourth contact.