What is a blue blood moon? Here’s what ‘blue moon’ actually means as it appears TONIGHT

Tonight marks the arrival of the first “blue moon” seen in UK skies since July 2015.

A blue moon is the name given to the second full moon in a single calendar month. The first one we had was back on New Year’s Day.

Despite the name, the moon isn’t going to appear blue. If anything, it will have a slightly reddish tinge. That’s because as well as being a blue moon, we’ll also be witnessing a lunar eclipse.

Some call it a “blood moon” and it’s when the reflection of sunlight on the Earth’s atmosphere hits the lunar surface.

A blood moon acquires a golden, copper, or even rusty-red colour depending on where the sun is – and it’s usually low in the sky or near the horizon.

Tonight’s moon event will also be, by definition, a supermoon – as the moon’s orbit will take it closer to the Earth than normal.

So, one way or the other, we’re set for quite the celestial show.

Here’s all you need to know about this month’s blue moon.

When will the blue moon take place?

January’s first full moon took place on the night of New Year’s Day and was also visible on the morning of January 2nd.

But the second – the blue moon – is taking place on the night of January 31.