In images, in picturesThe “Blood Moon” is observable when the Sun, the Earth and the satellite, in its full phase, are perfectly aligned. The phenomenon occurs twice a year.
Some Earthlings witnessed a total lunar eclipse on the night of Sunday May 16 to Monday May 17, an infrequent celestial spectacle during which the nocturnal star loses its brilliance and gradually turns red.
The eclipse was visible from parts of the American, European and African continents between moonrise and moonset – conditions permitting, including whether or not a layer of cloud was present. In mainland France, the eclipse was total at the end of the night between 5:29 a.m. and 6:54 a.m., with a maximum at 6:11 a.m.: the lunar disc was then completely red.
This phenomenon occurs about twice a year, when the Sun, Earth and Moon are perfectly aligned, and the Moon is in its full phase.
The star slips into the shadow of the Earth, which then shields the sun’s rays, and gradually loses its white glow.
But it does not go out for all that: the Earth continues to send light from the Sun back to the Moon, via rays which take on a red tint through a process of “refraction of the atmosphere”explains Florent Deleflie, from the Paris-PSL Observatory.
“During an eclipse, only the Earth can illuminate the Moon through this re-emission of red rays”continues the astronomer.
“It is very intriguing to see a white and brilliant Moon take on a red and extinguished hue over the minutes”, he adds. Visible with binoculars as with the naked eye, the phenomenon can give “spectacular pictures” if the weather conditions are good. The eclipse lasts about five hours, and its totality phase – when the star is completely in the Earth’s shadow – just over an hour.
“Observation from the West Indies or Guyana will be ideal, because the Moon will be very high in the sky”, according to the Observatory. The eclipse will also be visible in full in South America, Central America and the eastern part of North America.
The next total lunar eclipse is scheduled for November 2022, in the middle of the Pacific. In mainland France, the last dates back to January 2019 and the next one will not take place until 2029. Lunar eclipses have shown that the Earth is round “from antiquity”underlines the astronomer. “On the surface of the lunar disk, the limit between the shadow and the part illuminated by the Sun is slightly curved: it is the projection of the roundness of the Earth. »