Notice to insomniacs, young parents or party goers. And especially to astronomy enthusiasts. A total lunar eclipse will be visible overnight from Sunday to Monday from France, an infrequent celestial spectacle during which the nocturnal star loses its brilliance and gradually turns red. This phenomenon occurs when the Sun, Earth and Moon are perfectly aligned, in that order, and the Earth’s satellite is in its full phase.
The star then 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, through 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 via this re-emission of red rays”.
Visible with binoculars as with the naked eye
According to the astronomer, the spectacle is worth a look. “It’s very intriguing to see a white and bright Moon take on a red and extinguished hue over the minutes”, assures Florent Deleflie. Visible with binoculars as with the naked eye, the phenomenon can give “spectacular pictures” if the weather conditions are good.
The eclipse will be visible from parts of the American, European and African continents between moonrise and moonset. In mainland France, the eclipse will be 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 will then be completely red. Note that the Moon will set during this phase of totality, at the same time as the Sun will rise. It will therefore be all the easier to observe the phenomenon if you are in the west of France, where the Sun rises later than in the east.
“Observation from the West Indies or Guyana will be ideal”
“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 over an eastern part of North America. The Moon will be very low in the sky and to take full advantage of the eclipse, you will have to choose a place where the horizon is “cleared to the west”, advises Florent Deleflie.
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 “since antiquity” emphasizes 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.”