Friday, September 25, 2015

Superluna red, the sky from the show – National Geographic Italy

For amateurs, the night between 27 and 28 September provides a sight to the front row, with the convergence of three lunar events.

The first, the total lunar eclipse will coincide with what in English is called “Harvest Moon” , the harvest moon or the full moon closest to ‘ autumnal equinox. Our satellite will also at the point of closest approach to Earth (perigee moon); because of the apparent size of the satellite, in these cases are referred to colloquially superluna. That in the night between Sunday and Monday promises to be as a “superluna Red” in astronomical terms, a total eclipse central during lunar perigee.

This coincidence of events has occurred only five times since 1900. According to NASA, the last case occurred in 1982, and will not be repeated until 2033.

The most spectacular part of the eclipse will be that of the whole, that is, when the shadow of the

Ground cover completely the Moon, giving it a reddish hue. The phase of totality, where the shade is more intense, will last about 72 minutes.

The total lunar eclipse of these days is the fourth that has occurred in the course of two years: a tetrad that will not be repeated for twenty years.

What happens during an eclipse?

During a lunar eclipse, the Earth casts its shadow on the moon. This does not happen every time the moon revolves around our planet due to the inclination of the orbit, usually passes above or below the earth’s shadow.

The total eclipse of the moon, or as are popularly called, “red moons”, they are even rarer. Occur only during the full moon, and only when the Sun, Earth and Moon are aligned, so that the shadow of our planet completely dark lunar disk. This usually only happens twice a year, and the phenomenon can be observed only by one of the hemispheres land.

For thousands of years, the eclipses of our only natural satellite evoked wonder and ancestral fears . This eclipse will be even more special because the Moon will appear a bit ‘larger than normal: the lunar perigee will be only 59 minutes before the peak of the eclipse, and for this reason the lunar disk will appear about 13 percent larger than average .

Why the moon turns red?

During the total eclipse, the Sun’s light is refracted by Earth’s atmosphere toward the red end of the spectrum and projected onto the surface of the Moon. For this reason, we see the lunar disc move from the gray color during the step of partial darkening to orange reddish of the totality. The color of the satellite during the phase of obscuration total can vary greatly depending on the amount of dust present at the time the Earth’s atmosphere. For example, when the active volcanoes emit tons of ash in the upper atmosphere, which can lead to deep red eclipse.

But no one can predict what color we will see in the course of any given eclipse.

What happens now?

The first part of the eclipse, the partial obscuration, when the moon begins to enter the shadows ( Umbria ) cast by the Earth will begin at 2:07 am on September 28. The phase of totality is expected instead starting at 4.11 and last for about an hour and 12 minutes (with the peak at 4.47), after which the moon will begin to emerge from the shadow of the Earth. Around 7:23 will also come from the shadows, and the eclipse will end.

Who can see it?

The eclipse will be visible in the Americas, Europe and in Africa. Asia and the Pacific will, unfortunately, on the opposite side of the planet while the eclipse is in progress. Unlike solar eclipses, the moon can be seen in security to the naked eye.

And if you can not see it?

If you lose this eclipse, keep in mind that there will be no other for quite a while ‘. The next total eclipse is scheduled for January 31, 2018.

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