Rare Sacrifice Moon Moon coincides with Halloween for the first time in decades, illuminating the night sky.
The full moon will rise tonight after the sun sets on the last day of October.
This is the second full moon of the month, meaning it’s officially the “Sacrifice Moon”. The first full moon was October 1.
Having two full moons – or one blue moon – in a single calendar month is a very rare phenomenon that occurs almost every two and a half years.
The last time the full moon appeared on Halloween in all time zones around the world, as it would be tonight, was in 1944.
According to Astronomy Ireland, this is the first time since 1974 that Stargazers will be able to see a Halloween full moon in Ireland and the UK.
David Moore from Astronomy Ireland said Londoners should see the moon tonight because it will not be another 19 years.
“The full moon of Halloween probably happens a few times in every century and it will not happen again in Ireland and the UK until 2039,” he told the BBC.
“You associate Halloween with ghosts and demons, but this year the full moon will cause them to become ghosts.
“So, it’s good entertainment for the general public and hopefully it will inspire everyone.”
It is believed that the word Bali Moon was first used for the second full moon of the month in 1946 after a misinterpretation by an amateur astronomer.
Sacrifice Moon Moon meant the third full moon in the calendar month where four full moons were expected.
But allegedly, James Higgins Pryot misrepresented the second moon in a month as a Blue Moon in an article in Sky & Telescope magazine – and the name stuck.