A supermoon will be visible from Ireland tonight just after sunset.
This event can happen up to four times a year, with the moon at its closest point to the Earth, making it appear larger in the sky.
Chairman of Astronomy Ireland and Editor of Astronomy Ireland magazine, David Moore, said: "The moon goes around the Earth, not in a perfect circle, but in an ellipse, a sort of squashed circle, and the Earth isn't even at the centre of that it's off to one side.
“That means that at some stages of the moon's orbit, it can be about 15 per cent closer than at the other side of its orbit, and that results in the moon being potentially 30 per cent brighter… the very brightest moon you could ever see.”
Astronomers first discovered that full moons occur almost every 30 days. This is what led to our use of months.
Mr Moore said: “We quickly figured out thousands of years ago that there’s 365 and a bit days in the year, and then they also realised that there were 12, usually 12, sometimes 13, but usually 12 full moons every year.
“So the calendar was divided up into these moons or month, as we call them today.”
The supermoon will be at its best tonight but will also be visible tomorrow night.
He added: “You usually get two or three supermoons. We've actually got four of them this year, and this is the third one.”
Mr Moore explained that moonrise is the best time to see the supermoon for two main reasons.
He said: “The first thing is that the moon itself could be doing interesting things like lining up with buildings, statues or even people can get into the picture as well.
“And the second reason is, and this is very unscientific in a way, is that there’s a thing called the moon illusion.”
"For some reason, when the moon is very low on the horizon, and we think it's because there are round objects, trees, buildings, whatever the human eye thinks, the moon is a lot closer than it really is.
“Now, if you measure it with a telescope or something, you find out that it's exactly the same size… so it's definitely an optical illusion.”
Mr Moore encouraged people to send in their picture of the supermoon to Astronomy Ireland at magazine@astronomy.ie.
He said: “We want people to send us their best photograph, just one because we get flooded with pictures so we can record this supermoon in our magazine, which will be available to the public if they want it next month. The important thing is that you can get very creative.”
Another date for the astronomy diary is June 10, when there will be a partial eclipse of the sun when the moon passes in front of it.
Astronomy Ireland will be live streaming the event from their headquarters in Dublin on their website.
Mr Moore warned people to be safe while observing the partial eclipse.
He said: “Watching an eclipse of the moon is safe but, watching an eclipse of the sun is dangerous. If you stare at the sun, you can damage your eyesight. If you use binoculars of a telescope, you'll blind yourself before you can blink.”
