The UK will be treated to a total lunar eclipse on Monday morning, the last one was in July 2018, but because of cloud cover the view was not brilliant. Tonight’s spectacular event is the last chance for UK observers to see a total lunar eclipse in its entirety until 2029. A total lunar eclipse happen when the Earth passes between the Sun and the Moon and so the Moon moves into the Earth’s shadow – the umbra.
When this happens, the Moon turns a deep, dark red because it is illuminated by light that has passed through the Earth’s atmosphere and has been bent towards the Moon by refraction.
When the Moon is completely within the umbra, the darkest part of the shadow, it takes on a red hue that varies in colour, the Royal Astronomic Society explains.
“Sometimes the eclipsed Moon is a deep red colour, almost disappearing from view, and sometimes it can be quite bright,” the RAS said.
“The colour is due to Rayleigh scattering – where the Sun’s blue light is scattered off molecules in the Earth’s atmosphere – which also happens at sunsets.
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“The Sun’s red light is scattered much less by air, and is best by the Earth’s atmosphere in a process called refraction, travelling all the way through it to light up the Moon’s surface.”
How to watch the Super Blood Wolf Moon in Britain today
In the UK the eclipse will be visible on Monday, January 21, in the early hours of the morning.
The moon will enter the penumbra at 2.35am GMT and the umbra at 3.33am GMT.
Totality will begin at 4.40am, but the best time to view the eclipse is at around 5.12am GMT, when the moon will be completely submerged within the Earth’s shadow.
Totality last for around an hour, ending at 5.43am GMT – during this period the moon will appear completely red.
The Moon exits the umbra at 6.51am GMT and the eclipse comes to an end as it leave the penumbra at 7.49am GMT, just as the sun rises on Monday morning.
The entire eclipse will last for more than five hours.
The RAS said: “In the UK the Moon will be above the horizon throughout the eclipse, though from the extreme southeast of England the Sun will have risen as it comes to an end.”
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The total lunar eclipse can be viewed with the naked eye and with no special equipment.
To watch the eclipse on January 21, all you have to do is dress warmly and go outside.
The Royal Museums Greenwich is hosting a Facebook Live event from 8pm on Sunday, January 20, where viewers can watch events unfold.
The timings above are the best times to see the eclipse from London, but the times may differ slightly in other parts of the UK.