A rare "super moon" will make the full lunar disc appear 14% bigger and up to 30% brighter than usual as it rises above the rooftops tomorrow.
The event, described as "undeniably beautiful" by NASA, is the result of the moon coming closer to Earth than it has done for 69 years.
Nothing will match it until the moon makes a similar approach on 25 November, 2034.
At 11.23am the gap between the Earth and the moon will close to its shortest point, known as 'perigee' - a distance of 356,510km.
Sky watchers in Ireland will have to wait a little longer before the full moon emerges in all its glory shortly before 5pm.
On top of the moon's bigger than usual size, they will then be treated to an additional "low-hanging moon" effect.
This is an optical illusion caused by the moon being close to the horizon, where it can be measured against familiar objects such as trees and houses.
Robin Scagell, vice-president of the UK-based Society for Popular Astronomy, said: "It will be above rooftops and trees and chimneys and always appears bigger that way because you're comparing it to foreground objects.
"I'm always pleased for people to get their binoculars out and look up at the craters and the seas."
The last time the moon was this close to the Earth was in 1948.
