AN ECLIPSE OF THE SUN.

The moon casts a tapering shadow in space. when it passes between the earth and the Sun, the shadow,s tip may cross the earth, causing an eclipse of the sun. Inside the shadow the sun is blocked from view and all that can be seen in the dark sky is the Sun's corona. An eclipse is only total if seen from within the Moon's central shadow or umbra.
BEWARE !
You must NEVER look at the sun directly, either with naked eyes or through binocular or a telescope. The sun is very bright and will certainly damage your eyes. You may even be permanently blind.