Some earthlings will be able to witness a total lunar eclipse on the night from Sunday to Monday, an infrequent celestial spectacle during which the night star loses its luster and gradually turns red.
The eclipse will be visible from parts of the American, European and African continents between moonrise and moonset.
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 obscures the sun’s rays, and gradually loses its white glow.
But it doesn’t stop there: the Earth continues to send light from the Sun back to the Moon through beams that turn red as a result of the “atmospheric refraction” process, Florent Delefly of the Paris-PSL Observatory explains to AFP.
“During an eclipse, only the Earth can illuminate the Moon through this re-emission of red rays,” the astronomer continues.
Lunar eclipse May 16 (AFP – )
“It’s very interesting to see how the bright white Moon takes on a red and dull hue over time,” he adds. Seen through binoculars as well as to the naked eye, the phenomenon can produce “spectacular photographs” in good weather conditions.
The eclipse will last about five hours, and its full phase – when the star is completely in the Earth’s shadow – just over an hour.
“Observation from the West Indies or Guyana would be ideal because the Moon would be very high in the sky,” the observatory said. The eclipse will also be fully visible in South America, Central America and over eastern North America.
On mainland France, the eclipse will be total at the end of the night between 05:29 and 06:54, with a maximum at 06:11: then the lunar disk will be completely red. Note that the Moon will set during this phase of totality, at the same time that the Sun rises. Therefore, it will be easier to observe this phenomenon if you are in the west of France, where the Sun rises later than in the east.
The moon will be very low in the sky, and to take full advantage of the eclipse, you’ll have to choose a location where the horizon is “clear in the west,” Florent Delelieu advises.
The next total lunar eclipse is scheduled for November 2022 in the middle of the Pacific Ocean. In mainland France, the latest event dates from January 2019, with the next one not until 2029 at the earliest.
Lunar eclipses have shown that the Earth has been round “since antiquity,” the astronomer emphasizes. “On the surface of the lunar disk, the boundary between the shadow and the part illuminated by the Sun is slightly curved: this is a projection of the roundness of the Earth.”