Early risers in the UK will be treated to a partial lunar eclipse on Friday morning, when the moon will appear a deep blood red. The event follows a partial solar eclipse that occurred a couple of weeks ago, during which the moon covered roughly 90% of the sun, along with one of the year's best meteor showers and a parade of planets.
What is a lunar eclipse?
Lunar eclipses occur when the Earth slides between the sun and the moon. The darkest part of the planet's shadow, called the umbra, blankets the lunar surface, making it shine crimson instead of dusty white. There are three types of lunar eclipses: total, when the umbra swallows the moon whole; partial, when it takes a small bite; and penumbral, when only the outermost part of Earth's shadow, known as the penumbra, grazes past our celestial neighbour. The latter doesn't make the moon red but does darken it.
The red colour is not a sign of the end times. Even though it's nighttime, sunlight still leaks through the edges of the Earth, Jake Foster, an astronomer at the Royal Observatory Greenwich in London, told Metro. 'Our atmosphere then filters the sunlight that passes through it, allowing mainly red light to reach the moon and illuminating the lunar surface in an eerie red light,' he said.
What type will the UK see?
The UK will see a 'strong partial one', Foster said. 'Around 94% of the moon will appear red, with a small sliver maintaining its usual grey tones.' How red the moon becomes partly depends on how many particles are floating in our skies. Clouds, dust storms and anything else that whips up plumes can scatter blue wavelengths of light even more, making the moon appear a deeper shade of coppery red.
Lunar and solar eclipses always occur about two weeks apart – the amount of time it takes for the moon to move from one side of Earth to the other. Unlike a solar eclipse, lunar eclipses occur at the same time for everyone and happen slowly over several hours.
What time is the lunar eclipse?
The penumbral phase – when the moon passes Earth's shadow – will start from 2.23am and last until 8.01am. Around 94% of the moon will be covered by the Earth's shadow at 5:12am.
How can I see the lunar eclipse?
Unlike a solar eclipse, you can look up at this spectacle without the need for protective eyewear, such as eclipse glasses. Lunar eclipses can be seen with the naked eye, but binoculars or a telescope will help you get a better view, and you don't need a solar filter to see the blood moon with professional viewing equipment.
'Simply look towards the southwest to spot the moon,' Foster said. 'It will be fairly low during maximum eclipse, so a clear view of the southwestern horizon is recommended. The moon will set below the horizon around one hour after the eclipse's maximum, meaning UK viewers will miss the latter part of proceedings.'
How much of the blood moon you see will depend on how clear the night sky is. In a classic UK way, it's not looking too good. Timeanddate.com says that most major cities, including London, Cardiff and Glasgow, will be cloudy or rainy. You won't need to wait too long for the next one – a penumbral lunar eclipse will take place between February 20 and 21 next year.
