Blood Moon: What is the lunar eclipse tonight and how can I see it?

27 July 2018, 10:17 | Updated: 30 July 2018, 11:56

The longest lunar eclipse of the century is coming on Friday...

Here's all the info you need about the upcoming 'Blood Moon':

What is a Blood Moon?

It occurs when the Earth passes between the sun and the moon, casting the moon into shadow.

It is different to a solar eclipse, when the moon passes between the Earth and sun, blocking the sun’s light. Here, the moon doesn't turn 'dark' during an eclipse, but instead appears to turn red. Sweet!

“If the Earth was a big smooth ball with no atmosphere that would be the end of the subject, it would just go dark, like with a new moon,” Chris Tinney, professor at the University of New South Wales explained to the Guardian.

“But because there is light scattered through the atmosphere of the Earth, some of the sun’s light gets bounced around the edge of the Earth to hit the moon.”

As blue and violet wavelengths are scattered more than red and orange ones, the red wavelengths reach the moon more than the others, making the moon appear red.

How often does this happen?

Lunar eclipses are far less common than solar eclipses, with a maximum of three happening in any given location per year, and in some years there have been none at all.

Each lunar eclipse is visible from more than half the Earth. This particular eclipse is rather rare, because it will last for so long.

The moon will be in the Earth’s shadow for a total of four hours and totally eclipsed for one hour and 43 minutes, which is only just a tad shorter than the theoretical limit of a lunar eclipse (which is one hour and 47 minutes).

When and where can I see the Blood Moon?

Well, the absolutely best view of the eclipse will be from east Africa, the Middle East, India or the westernmost tip of China.

However, there should still be decent views for people in Africa, Europe, other parts of Asia, Australia and the eastern tip of South America.

Only North America and Greenland will likely be the only places that will miss out on seeing it entirely.

In the UK, the partial eclipse will begin at 8.30pm on Friday (July 27), the total eclipse will happen between 920pm on Friday, with the moon visible to the south-east, until 10.13pm.

Plus, it is perfectly safe to look at lunar eclipses.

“The best place to see it is out in the country away from lights,” Tinney added. “If you’re living in [a city] then there’s a lot of light pollution from the night sky, so the contrast between the moon and the sky won’t be as great.”