Visible across Europe, a total lunar eclipse will make for a spectacular sight during May 15 and 16 2022. 

The eclipse, which does not require binoculars or a telescope to be seen, will also make for a perfect target for astrophotographers. 

A lunar eclipse occurs when the Earth moves between the Sun and the Moon, and the shadow cast by the Earth covers the Moon. For the spectacle to happen, there must be a full Moon and the alignment between the Moon, Sun, and Earth must form a line. 

In astronomy, this type of alignment is referred to as syzygy, taken from the Greek word and basically meaning being paired together.

The shadow cast upon the lunar surface can be separated into different parts.  The first part being the umbra, the darker central part of the shadow. The second being the penumbra, the outer part of the shadow. 

Even though the Earth will be totally blocking out the sunlight reaching the lunar surface during the eclipse, we will still be able to see the Moon with the naked eye. 

This is because the Earth’s atmosphere bends sunlight and indirectly lights up the lunar surface. 

As this refraction takes place, colours with shorter wavelengths become filtered out, whilst the likes of orange and red, both of whom have longer wavelengths, are left to ‘colour’ the Moon, hence the reference to a ‘Blood Moon’

How and when to watch the Eclipse

The eclipse takes place in the early hours of the morning of Monday May 16, with totality, (the moment when the Moon is completely covered by the Earth’s shadow), taking place just before the Moon sets below the horizon.

02:32 – The penumbral phase of the eclipse commences as the lunar surface enters the outer part of the Earth’s shadow. This part of the eclipse may well be difficult to spot at first but as the Moon moves deeper into the shadow the transition will become more and more apparent. Keep an eye on the western limb of the Moon for the shadow moving across the lunar surface.

03:27 – The Moon enters the umbra, the darker part of the Earth’s shadow. This will be more noticeable than the penumbra. At this point, the Moon will also be starting to take on a reddish appearance.

04:29 – The total eclipse begins as the Moon takes on a becomes completely reddish in appearance. At this point, the Moon is also heading toward the horizon, which is why having a good view of the south-western horizon is important.

05:11 – This is the point of greatest eclipse, when the Moon is closest to the centre of the shadow cast by the Earth. However, the Moon is now very close to the horizon and depending on your vantage point, it may be tricky to actually spot the eclipse any further. A bright full Moon can be spotted in these circumstances when it’s near to the horizon, but an eclipsed Moon will be difficult to see.

05:21 – At this point, the Moon will set but there’s a strong possibility that it may already be lost from view.

Make the most of this opportunity because the next total lunar eclipse visible from Wales won't be until March 14, 2025.