> Activities > Solar
Telescope Making Workshop
Campaigns and Activities
on Solar Eclipse
Solar Viewing Filters
What is Solar Eclipse ?
An eclipse of the sun occurs when the moon revolving in its orbit around
the earth comes between the sun and the earth. The moon blocks the light
of the sun and a shadow of the moon is cast over the earth's surface..
How does the moon block the sun?
By a fortunate coincidence, the sun's diameter is 400 times larger than
that of the moon, and at the same time, it is 400 times as far away.
From where we are, this creates the illusion that they are the same
size. If we look through a filter at the sun, it looks exactly like
the moon on a full moon night. When the moon passes in front of the
sun, the shadow falls on the earth and it appears to exactly cover the
sun's disc. This is what a solar eclipse is - a shadow.
Is it evil to watch Solar Eclipse ?
In essence, an eclipse is no more evil than the shadow of a tree, or
a tall building. The moon just blocks off the light of the sun for a
brief, beautiful moment.
Where can we see this ?
During a solar eclipse, the moon actually casts two shadows towards
earth. One shadow shaped like a cone is called the umbra. This becomes
narrower as it reaches the earth. No direct sunlight penetrates into
this area. The path of this is called the path of totality. If you are
positioned in this area than you can see a complete blocking of the
sun and view a total solar eclipse. Total eclipse is observable only
within a narrow strip of land or sea over which the umbra passes.
The second shadow is called the penumbra which spreads
out as it reaches the earth. The penumbra is spread over a large area.
People viewing the eclipse from this area of the earth's surface will
see only a partial blocking of the sun.