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Lunar Eclipse

Lunar Eclipse

 Automatic translationAutomatic translation Category: Eclipses
Updated November 10, 2013

lunar eclipses are eclipses of the moon by the Earth whereas solar eclipses are eclipses of the Sun by the Moon.
This heavenly match has frequently observed in human Antique aware of the roundness of the Earth.
Lunar eclipses are observable to the same moments in the same aspect since all places on the surface of the Earth when the Moon is above the horizon and the sky is not obscured by clouds.
The Moon orbits the Earth and back in front of the Sun 29 days 12 hours 44 minutes 2.9 seconds on average. This period is the synodic revolution or lunation. It is readily apparent in observing the moon with the naked eye that his shape and position in the sky change from day to day.
This phase of the moon is due to the change of positions on the Moon, the Sun and Earth, and the fact that the Moon does not emit light itself but thought that it receives Sun.
What makes you see that the illuminated portion that faces the Ground.
A lunar eclipse occurs when the Sun, Earth and Moon are nearly aligned in that order.

 

It is therefore lunar eclipse during a full Moon. When the eclipse is total, the Moon enters at different points in the cone of darkness and shadow drawn by the Earth opposite the Sun. If the moon moved around the Earth in the same plane as the Earth around the Sun, the ecliptic plane, there would be a lunar eclipse every full moon, so every 29.5 days.
In fact the orbital plane of the moon and the ecliptic plane make an average angle of 5 ° 9 '.
This makes the alignment of three bodies can occur only if the Moon is very close to the ecliptic plane (also for this reason that the plan was so named). Eclipses of the Moon, though less dramatic than solar eclipses, cons are visible in all places where the sun is above the horizon, that is to say a little more than half of our planet.
It is not uncommon to see several every year.
There 'Full Moon' when the lunar disk is fully illuminated, the Moon is located opposite the Sun.

 éclipse de Lune

Schema of principle

    

Image: The image below shows cons on a diagram of a lunar eclipse, the trajectory of it through the cone of shadow and darkness of the earth.
Inside the cone of shadow, the sun is totally obscured by the Earth and the dark of the moon is full.
In the cone of darkness, the sunlight is partially visible and the brightness of the Moon is only attenuated, the more so as we approach the edge of the cone of shadow.

 ombre d'une éclipse de Lune

Proceedings of the eclipse

    

The beginning of the eclipse begins when the Moon enters the penumbra of the Earth (the entry in the shadows, although it has a precise geometric sense, is virtually indistinguishable to the naked eye). From that moment, the Moon is gradually losing its shine.
Entering the shadow is the beginning of the partial eclipse. When the moon begins to enter the umbra of the Earth, a dark recess, increasingly important, gradually hiding the lunar disk already tarnished, sparing soon clear that a growing (if the limit shade is very clear to the naked eye, it is much less in a pair of binoculars, a telescope or a telescope).
The reddish color characteristic of the shaded area becomes visible for the attenuation of the brightness of illuminated part, and grows up to hide our comprehensive satellite in Earth's shadow.
During the eclipse by the shadow of the Earth, the Moon is at this moment completely immersed in the shadow of our planet without disappearing completely.
Indeed, the moon dimly lit by the rays of light refracted by the atmosphere, is adorned with a beautiful reddish color from red to coppery red.
At maximum eclipse, the moon is in the umbra of the Earth, but nothing in particular to allow observers to realize. The end of the eclipse by the shadow of the Earth occurs when the Moon begins to leave the umbra of the Earth. From that moment, a clear increasing, more and more, gradually invades the lunar disc yet dulled, sparing soon a dark notch.
The reddish color characteristic of the shaded gradually diminishes until the full release of our satellite of the Earth's shadow. It's the end of the partial eclipse when the Moon completely leaves the umbra of the Earth.

 

From that moment the moon emerged gradually from outer shadow and finds all his brilliance, which dazzles our eyes (for the same reasons as for the entry, the observer has the impression that the eclipse is over well before leaving the darkness that is indistinguishable).

Image: Photography of the entry of the Earth's shadow on the Moon.


éclipse
 éclipse

Image: Photography of the exit of the Earth's shadow on the Moon.

The eclipsed Moon is still visible

    

It is interesting to note that at the heart of the eclipse the moon does not disappear, although it is in the shadow of the Earth.
This is due to our atmosphere bends the light rays that pass through it and which also transmits more blue than red.
As a result of sunlight illuminate the moon just when it is located in the cone of shadow, and that these rays are bearers of light rather than red, hence the reddish hue of the moon.
This color can range from vermilion clearest to darkest brown, depending on the amount of impurities in the atmosphere and the distance from Earth to the Moon.
Conclude by stating that, as everyone knows, we may look at the moon with the naked eye safe, unlike the Sun.
We can therefore follow the different phases of the eclipse with the naked eye or better with binoculars or any other instrument to distinguish between the disappearance and reappearance of the main details of the lunar terrain.

 

Image: Photograph of the Moon when it is obscured by the shadow of the Earth.

 éclipse de Lune
           
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