Crowds worldwide treated to the largest moon in almost 70 years.iStock

Astronomy Ireland is looking for the best photos of last night’s supermoon, the largest to appear in 68 years.

A supermoon is a name given to the rare natural phenomenon when a full moon occurs at the very same time that the moon is at its closest point to the Earth--known as perigee--caused by the fact that the Earth’s satellite does not travel around us in a perfectly circular orbit.

The distances of the orbit can vary by as much as 14% and on Monday evening, the celestial body circled the Earth at a distance of 218,614 miles.

When this coincides with a full moon, the moon can appear as much as 30% larger to the naked eye. Watching the moon as it rises, however, will also create an optical illusion, known as the low-hanging moon effect, that will make it appear significantly increased in size.

To mark the event, the Irish organization is holding a competition to find the very best images of the rare spectacle.

"For previous Supermoons we have been flooded with photos from all around Ireland so we wanted to do something very special for this year's Supermoon which will be best of the period 1948 to 2034, which is almost century!” writes David Moore, Editor of Astronomy Ireland magazine and Ireland's best known astronomer, on the organization's website.

“Now, Irish people can get involved in a very real and fun way and enter our competition. We hope skies will be clear all over Ireland and wish everyone great success."

Although a supermoon generally occurs about once every 14 months, we will not witness the phenomenon throughout 2017 and we won’t find it breaking records again until 2034 (November 25, if you want to mark your calendars in advance). Last night was the largest the moon has appeared in the sky since 1948.

Read more: Cloudless sky offers perfect view of Ireland from space (PHOTOS)

Viewing parties were held worldwide to witness the incredible spectacle, while photographers set out to capture this almost once in a lifetime opportunity, an event NASA described as “undeniably beautiful.” Such was the moon's brightness that even light pollution from streetlights and surrounding buildings could not diminish its glow.

As a result of the supermoon, tides were also given a small boost and surfers around Ireland took advantage of its influence on the waves, as well as its provision of extra light that made nighttime surfing all the easier.

And if you missed the show last night due to cloudy weather, don’t worry. The moon will not appear much smaller this evening, and though not exactly a supermoon, will look stunning as it rises in the evening nonetheless.

"The Moon looks 'Full' to the naked eye for three days. So, people should watch on Sunday and Tuesday night as the view will be almost as spectacular," Moore stated.

Think you have the best supermoon photograph? Send your submission to [email protected].