Those celebrating Halloween tonight are in for a rare treat as there will be the first full moon over NI for 46 years.
There has not been a full moon on Halloween in Northern Ireland since 1974, with tonight proving to be especially rare, as it is the second full moon in October, also known as a Blue Moon.
Astronomy Ireland says that there will not be another full moon on Halloween until 2039.
Blue moons usually only come every two or three years, with the next not appearing until 31 August 2023.
Contrary to popular belief, a blue moon has nothing to do with the colour of the moon. Instead, it’s all to do with the timing of full moons during the year.
Astronomy Ireland said: "Not since 1974 has Ireland had a Full Moon occur on Halloween, nor will there be another one until 2039.
"So the Full Moon on October 31st in 2020 is very rare.
"It is also the second Full Moon in October 2020 (the first was on October 1) and these rare 'second Full Moon in the same calendar month' have become popularly known as a 'Blue Moon'.
"Like the saying 'once in a Blue Moon' they are quite rare and only occur every 2 or 3 years on average.
So Halloween 2020 is very special as it is so rare to have a Full Moon on Halloween, and it is a Blue Moon also."
The organisation says that people should watch from sunset, at around 5pm, when the moon is rising on the exact opposite side of the sky as the setting sun.
It said: "The rising Moon can 'look big' due to an optical illusion known as the 'Moon illusion' and can trick the eye/brain into thinking the Moon is 2 or 3 times bigger than it really is!"
