A solar eclipse is a phenomenon known optical dimming of all or part of a hard sun by the moon as seen from Earth that occurs during the new moon . It is a rather rare event Sun, Moon and Earth must be perfectly aligned in this order this is only possible when the Moon, whose orbit is tilted five degrees from the ecliptic intersects it in a point called node. When the node is located between the Earth and the Sun, the Moon's shadow passes in some parts of the earth's surface and there is a solar eclipse. If the node is located on the opposite side, it has a lunar eclipse.
A lunar eclipse is a well-known optical phenomenon in which the shadow of the Earth obscures all or part of the Moon and that occurs at the moment when it is being full while the Sun , Earth, and it can be found aligned in that order. Because of the mutual distances between the Sun, the Moon and the Earth's shadow that is introduced by the interposition of the latter body is conical in shape. In a lunar eclipse the shadow cast by the Earth is always much broader than the Moon, and is accompanied by a wider cone, said cone of penumbra , in which only part of the Sun's rays are intercepted by the Earth.
Today, scholars can easily have a few programs that can calculate with great accuracy and the special numerical tabulations that have been mentioned above and is drawing its forecast maps. These are just some of the world maps with overlapping curves representing the geographical limits of the north and south end of totality and its line of centrality to the ground. These curves are obtainable even for the partial eclipses.
Through these programs even amateurs could fairly easily verify that the northern limit of the total eclipse of the sun of the year 2027 will touch a part of the territory of the Italian Republic: in fact, as has been said, it will be in full right the first eclipse visible as a total and immediately following, in chronological order to the one that occurred Feb. 15, 1961.
During the total eclipse the Moon is not completely ceases to receive light; sunlight through the atmosphere Earth is mainly diverted for refraction and reaches the satellite, giving it a color that was observed during the changing of the same eclipse: it goes from dark red cupric to orange red through other shades including the brown and blue - dark green. These colors can be seen coming from the Moon are also due to the particular area of the earth that reflects the rays, which could be rich in water (oceans) and forests, resulting in chromatic dominant.
The duration of the total eclipse of the Moon can reach 100 minutes. The Moon crosses the shadow cone with a speed, that of the motion of revolution of the moon, significantly lower than that of rotation of the Earth, which determines the duration of solar eclipses in a given place.
The type of phenomenon most studied and best known in the field of astronomical observations is the 'total eclipse, because during the middle phase can be studied with ease the solar corona ; why this occurs it is necessary that at the time of the solar eclipse the Moon is at a distance from Earth that make it appear to the angular diameter slightly greater than that of the Sun. If this does not happen, ie the Moon showed an apparent angular diameter of less than that of the Sun will be seen a bright ring is not desirable for the observation of the crown: this configuration is indicated by the expression annular eclipse .
Ultimately the total eclipses occur when, in a moment of time, the apparent angular diameter of the Moon is almost equal to that of the Sun and the Sun, Moon and Earth are perfectly aligned in that order. That instant of time is to be expected with a good approximation by the calculations provided for periods not too far away from the current. Due to the varying distances from one another (which occur during the duration of an eclipse) between the Earth, the Moon and the Sun could happen that an eclipse is observed as the total for some places land, while as a ring to the other. This event is usually referred to by the name of hybrid eclipses .
Depending on the distances that exist between the Moon and the Earth may apply four types of eclipses briefly described here. For all those who will be fascinated by the eclipse in Kolkata, and will want to repeat the experience, here are the dates of the next total eclipse. The next lunar eclipse is October 8, 2014 and the next solar eclipse is October 23, 2014, which will be visible in some parts of the world.