The longest partial lunar eclipse in 580 years will occur this Friday (19) and can be seen from Brazil.
At the height of the phenomenon, the Moon will have more than 97% of its surface covered by the Earth’s shadow and will take on a reddish appearance.
Partial eclipses are more frequent than total eclipses, though less spectacular.
The phenomenon can be seen across North America, as well as large parts of South America, Polynesia, eastern Australia and northeastern Asia.
The partial eclipse starts around 4:19 am EDT, and should last just over 3:00 am. However, it can be observed an hour earlier, when the Moon enters the Earth’s penumbra (outer part of the shadow). At that point, the satellite darkens, albeit subtly.
The peak should happen at 6:00 am, but as the Moon will already be below the horizon in Brazil, it will no longer be possible to see it.
For Brazilians, the best time to observe the phenomenon will be right at the beginning, around 4:00 am, when the partial eclipse actually starts. Visibility will depend on weather conditions.
The eclipse will be more visible in the North region than in the South of the country.
Origin and red color
A lunar eclipse occurs when the Sun, Earth, and Moon align so that the Moon passes through the Earth’s shadow. In a total lunar eclipse, the entire Moon is covered by Earth’s shadow, called an umbra.
During the phenomenon, the Moon acquires a reddish color.
The phenomenon, called Rayleigh Scattering, is the same one that explains “why blue skies and red sunsets,” according to NASA.
“Light travels in waves and different colors of light have different physical properties. Blue light has a shorter wavelength and is more easily spread by particles in Earth’s atmosphere than red light, which has a longer wavelength, Red light, on the other hand, travels more directly through the atmosphere,” NASA says on its website.
“When the sun is up, we see blue light across the sky. But when the sun is going down, the sun’s light must pass through more atmosphere and travel farther before it reaches our eyes. The sun’s blue light spreads out. and the longer wavelength red, orange, and yellow light passes.”
“During a lunar eclipse, the Moon turns red because the only sunlight that hits the Moon passes through Earth’s atmosphere. The more dust or clouds in Earth’s atmosphere during the eclipse, the redder the Moon will appear. It’s like every sunrise. and sunsets of the world were projected onto the moon,” adds the agency.
During the eclipse, the Moon moves through the western part of the constellation Taurus.
In this way, a closer observer can see the Pleiades star cluster in the upper right corner, and the Hyades cluster — including the bright star Aldebaran, the bull’s eye — in the lower left corner.
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