A solar eclipse occurs when Sun, Moon and Earth are on a single line, the Moon being in the middle. Seen from the Earth, the Moon is in front of the Sun and thus part or all of the light of the Sun is hidden by the Moon. Thus, it seems that a piece is taken out of the Sun, or even that it has suddenly disappeared in the middle of the day. There are three types of solar eclipses:
- A partial eclipse: Only part of the Sun and the Moon overlap
- A total eclipse: All of the Sun is hidden by the Moon
- A ring-formed eclipse: The Moon is in front of the Sun, but does not completely cover it, the Sun forms a ring around the dark space formed by the Moon.
A solar eclipse can only be seen in a band across the Earth, while a total eclipse is actually total in only a small band within this band, and partial elsewhere. Solar eclipses are a rare and spectacular occurence.
For astronomers, a total solar eclipse forms a rare opportunity to watch the corona, the outer layer of the Sun. Normally this is not visible because the light of the Sun itself overshines it.