A NORMAL LUNAR ECLIPSE
The Moon shines because its surface reflects the Sun's rays, thus it is a luminous body. A lunar eclipse happens when the Earth comes between the Sun and the Moon and blocks some or all of the Sun's light from reaching the Moon. The imperfect alignment of Sun, Moon and the Earth causes Penumbral lunar eclipse. This type of eclipse is often mistaken as normal full moon day.
WHAT IS PENUMBRA ?
Penumbra is lighter and outer part of shadow of any celestial bodies like Earth and Moon whose shadow is responsible for eclipse.
Moon penumbra causes partial solar eclipse.
Earth penumbra causes partial lunar eclipse.
When the Earth enters the Moon's shadow, we see a solar eclipse; when the Moon travels through the Earth's shadow, a lunar eclipse occurs. The type of eclipse depends on the type of shadow that is involved.
Like any other opaque objects illuminated by a light source, the Moon and the Earth cast shadows into space as they block the sunlight that hits them. Each shadow has 3 different areas:
The umbra
The penumbra
The antumbra.
In penumbral lunar eclipse we can't see the dark bite appear on the moon, but during mid eclipse we will observe the shading on moon surface, the shading is nothing but the earth penumbral.
About 35% of lunar eclipse are penumbral
30% are partial lunar eclipse
35% are total lunar eclipse.
In a partial lunar eclipse, the umbra takes a bite out of only a fraction of the moon. The dark bite grows larger, and then recedes, never reaching the total eclipse.
In a total eclipse of the moon, the inner part of Earth’s shadow, called the umbra, falls on the moon’s face. At mid-eclipse, the entire moon is in shadow, which may appear blood red.
Between June 5 and June 6 2nd penumbral lunar eclipse of 2020 will occur.
The Moon shines because its surface reflects the Sun's rays, thus it is a luminous body. A lunar eclipse happens when the Earth comes between the Sun and the Moon and blocks some or all of the Sun's light from reaching the Moon. The imperfect alignment of Sun, Moon and the Earth causes Penumbral lunar eclipse. This type of eclipse is often mistaken as normal full moon day.
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| penumbral moon image credit : wikipedia |
WHAT IS PENUMBRA ?
Penumbra is lighter and outer part of shadow of any celestial bodies like Earth and Moon whose shadow is responsible for eclipse.
Moon penumbra causes partial solar eclipse.
Earth penumbra causes partial lunar eclipse.
When the Earth enters the Moon's shadow, we see a solar eclipse; when the Moon travels through the Earth's shadow, a lunar eclipse occurs. The type of eclipse depends on the type of shadow that is involved.
Like any other opaque objects illuminated by a light source, the Moon and the Earth cast shadows into space as they block the sunlight that hits them. Each shadow has 3 different areas:
The umbra
The penumbra
The antumbra.
 |
| a normal full moon on left and penumbral lunar eclipse |
As some sunlight still reaches all of the Moon's surface directly during penumbral lunar eclipses, they are usually fairly unspectacular. In fact, if the Moon only enters the lighter outer parts of the penumbra, this type of eclipse may even be difficult to distinguish from a normal Full Moon.
The Earth's penumbra is also involved in partial and total lunar eclipses. It covers the Moon's surface before and after the Earth's umbra envelops it. However, this usually goes unnoticed because the phases involving the umbral shadow are much more spectacular.
For penumbral lunar eclipse to occur
- The Moon must be in the Full Moon phase.
- The Sun, Earth, and Moon must be nearly aligned, but not as closely aligned as during a partial eclipse.
How lunar eclipse occurs ?
The orbit axis of Moon rotating around the Earth is inclined at an angle of 5 degree to orbital axis of Earth. The point where these two orbital points are meet know as lunar node. Lunar
eclipse happen only when the full moon occurs at the lunar node, this is why we are not seeing the lunar eclipse every full moon day. for the lunar eclipse to happen the moon should be at the lunar nodal point. In penumbral lunar eclipse we can't see the dark bite appear on the moon, but during mid eclipse we will observe the shading on moon surface, the shading is nothing but the earth penumbral.
About 35% of lunar eclipse are penumbral
30% are partial lunar eclipse
35% are total lunar eclipse.
In a partial lunar eclipse, the umbra takes a bite out of only a fraction of the moon. The dark bite grows larger, and then recedes, never reaching the total eclipse.
In a total eclipse of the moon, the inner part of Earth’s shadow, called the umbra, falls on the moon’s face. At mid-eclipse, the entire moon is in shadow, which may appear blood red.
Between June 5 and June 6 2nd penumbral lunar eclipse of 2020 will occur.
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