What is eclipse? It can be described as an astronomical event that occurs when an Celestial body become temporally obscured , when it pass into the shadow of another body or by having another body pass between it and the viewer .Eclipse is often used to explain either a solar eclipses or lunar eclipses (eclipses of the moon)
Before we continue not that the sun produces it own light , and therefore it is called luminous object, but moon and earth, cannot produce their own light and therefore they are called non-luminous objects. So the moon can only be seen when sunlight reflects from the body of moon.
Umbra and penumbra
Before we talk about Umbra and penumbra, we first of all talk about the shadow. A shadow is formed be an opaque object, that an object that does not allow light to pass through it.
What is a shadow? It is that area to which light cannot reach because of the obstruction by an opaque object.
So umbra is inner shadow, an area where light did not reach at all, while penumbra is partial shadow, which is an area that received part of the light ray.
Solar eclipses (or eclipses of the sun)
The solar eclipses take place when moon comes between the sun and the earth, the moon’s shadow is cast on the earth, so people that are viewing from umbra, for them it is total eclipse, but for people at penumbra is a partial eclipse. The solar eclipses occur about 2 to 5 times a year, depending on geometry of the sun, moon and Earth.
Total Eclipses, Annular Eclipses, and partial Eclipse of the sun
The total eclipses of the sun occur when the moon completely obscures the sun, so that only the solar corona is showing. The total eclipses of the sun occurs once 1 to 2 years.
Annular Eclipse of the Sun
This occur when sun and the moon are in positions where the end rays intersect before reaching the earth , so the sun (corona) is then covered , leaving a bright ring around the edge. This type of eclipse exposes the outer part of the sun which has be obstructed by moon.
Lunar eclipse (or eclipse of the moon)
It takes place when the earth is between the sun and the moon, so the shadow of earth is thrown upon the moon, therefore the total or partial eclipses of the moon is observed
Important of eclipse
1. The annular eclipse of the sun, gives astronomers opportunity to study the properties of the outer part of the sun (corona)
2. It helps us to learn about the mechanics of the solar system
3. It is one of the evident that the earth is not flat.