Europeans, Africans, Asians and Australasians will be able to watch the Earth’s shadow pass over the Moon on Friday, June 5, as 2020’s eclipse season resumes.
A fine penumbral lunar eclipse will be visible to most regions of the world, inviting people to look upwards.
It is the second of four lunar eclipses to be expected this year, and the last to be visible from the UK.
But what will it look like, and how do you catch it? What even is a lunar eclipse, and a penumbral one at that? Here’s your guide to Friday’s astronomical event.
(EPA)
How to watch the lunar eclipse
The eclipse will begin on June 5 at 6:45pm BST, and finish at 10:04pm.
Lucky Brazilians may catch a glimpse, along with West Africans and Europeans at moonrise in their countries. East Africans and Asians will see the entirety of the eclipse, but Central and North Americans will have to wait till next time (specifically, until July 5).
For UK-viewers, the eclipse will reach its greatest visible magnitude at 9:06pm: get outside beforehand.
Since the moon will be near the horizon at the point, it is a good idea to head high if possible, and seek out clear views to the southeast.
What is a Supermoon?
What will it look like?
Truthfully, not a whole lot different; the moon will very much still glow.
This eclipse is a penumbral one, which means it is peripheral.
Rather than the Earth’s main shadow - the umbra - covering the moon, penumbral eclipses involve the weaker, outer shadow passing, meaning the visible change is only slight. The eclipsed segment of the moon will be faintly darker than the rest of it.
When the Moon passes through the Earth’s inner, darker umbra, Earthlings can see a dramatic reddening.
The colour of the whole moon may also become slightly browner.
The most impactful moment of Friday’s eclipse will saved for viewers in the remote sea off the eastern coast of Madagascar: it will be a very intimate audience.
For readers on the Moon, it will be a more dramatic event, as the Earth comes to partially eclipse the sun.
Lunar eclipses explained
A lunar eclipse occurs when the Earth passes directly between the Sun and Moon, casting a shadow over the latter.
The irregularity of these is explained by divergence between the Moon’s orbit and the Ecliptic Plane.
The Ecliptic Plane is the line that would circle the Earth if we traced in pen the Sun’s route across our sky; essentially, it is our solar orbit.
If the Moon orbited exactly along this line, we would have two eclipses each month — one lunar and one solar.
Instead, the Moon’s orbit is inclined about five degrees relative to the Ecliptic Plane. Consequently, the number of orbits we see varies year by year.
One calendar year has a minimum of four eclipses (the total number in 2020), but in 1982, there were seven.
