Stargazers are in for a treat this weekend as a rare astronomical event is about to take place.
Those looking upwards late in the evening should, weather being kind, a special full moon.
In fact it only appears once every two years and is called a Full blue Moon.
A full moon appears when the moon is situated on the opposite side of the Earth as the Sun. This means its face is fully illuminated.
But even though we call it a Full Blue Moon - it doesn't actually look blue in the sky.
It gets its name because it's the third of four full moons in this season.
There are usually three full moons in a season so the event is pretty rare. This is why people often use the phrase ‘once in a blue moon’.
NASA told The Mirror : "A blue moon is special because it is the 'extra' Moon in a season with four full moons. This usually only happens every two-and-a-half years."
Early Native American tribes also referred to the spectacular as the Full Flower Moon due to the fact that it shows itself in spring - the same time as flowers start to bloom.
When can I see the full moon?
If you want to be in with a chance of seeing the Blue Moon, you're best off looking from around 21:11 BST.
If you miss it this week you'll have to wait a while to see another one as the next Blue Moon won't be visible until August 22, 2021.
