The world is getting ready to see a Total Eclipse of the Moon tonight.
The moon will turn a deep rusty red, as well as appearing bigger and brighter than normal.
The eclipse will last between 2am-6am, centred around 3:47am, and will be visible from most of Europe and North America.
David Moore, Chairman of Astronomy Ireland says tonight's eclipse will be particularly clear.
"If you don't like the prospect of getting up in the middle of the night to see this amazing spectacle of the Full Moon dropping in brightness by nearly a million times, our calculations show that you will have to wait until December 20, 2029 to see the next Total Eclipse of the Moon from Ireland in an evening sky," said David Moore, editor of Astronomy Ireland magazine.
"We are advising every working person in Ireland to book a day's holiday for Monday so they can stay up late Sunday night and watch the entire eclipse!"
There has not been a Total Eclipse of the Moon visible in Ireland since December 21, 2010 and that too was in the small hours so very few people have ever seen what is one of the most spectacular sights in nature.
During the eclipse, the bright Full Moon that lights up the entire sky will fade and almost vanish.
All that will be left will be a dull coppery-red Moon perhaps one million times dimmer than the Full Moon. This will last from 3:11am to 4:23am.
But the hour before this and the hour after this is equally impressive as the Moon slips into and out of the Earth's shadow.