The night sky has been illuminated by what appears to be a much bigger and brighter Moon.

The so-called "supermoon" occurs when the Moon reaches its closest point to earth, known as a perigee full moon.

The effect makes the Moon seem 14% bigger and 30% brighter than when it is furthest from the planet.

Skywatchers who miss the phenomenon this weekend because of cloudy skies will have to wait until August 2014 for the next one.

Space expert Heather Couper said "supermoons" were the result of coincidence.

"The Moon goes round in an oval orbit so it can come very close to us, and if that coincides with a full moon, then it can look absolutely enormous,when the Moon was high in the sky, it looked normal.

But as it got closer to the horizon, a "kind of optical illusion" occurred where it looked bigger when compared with trees or house

Writing in Sky and Telescope about the "myth of the supermoon", Shari Balouchi said much of what we called the supermoon was just our eyes playing tricks on us.

"The supermoon might look bigger than normal if you see it in the evening when the Moon's just rising, but the real size difference isn't big enough to notice."

However Marek Kukula, public astronomer at the Royal Observatory Greenwich, said people should not expect the supermoon to look that much bigger than normal.

"It won't fill the sky," he said.

"It's at its most impressive when the Moon is close to the horizon, ie when it's rising or setting - people will need to check online for rising and setting times for their locality."

Dr Kukula said the US Naval Observatory and HM Nautical Almanac Office had online tools for checking the moon's rising and setting times.

Scientists have dismissed the idea that the perigee can cause strange behaviour, like lycanthropy or natural disastre.

Gaze up at the sky tonight to catch a glimpse of a rare 'super' supermoon, the huge perigee moon that will be shining brightly over this weekend.

The super moon which will occur tonight and on June 23, will appear to be bigger than the average full moon as it will be lined up with the sun perfectly so that the moon will appear to be brighter and bigger.

The moon will be at its closes point to Earth on June 23 at 7:32 a.m. EDT but will appear just as big tonight.

This weekend's super moon is known as a "perigee" full moon, which means that it's orbit is closes to the center of Earth in a month. Full moons do no necessarily happen during a perigee but when it does, it means the sun, earth and moon align. Another super moon like this will not be seen until August 2014.

The perigee and full moon this month will only be an hour apart.

Sunday's super full moon means that the moon will be 221,824 miles away from Earth. The period where the moon orbits furthest from Earth is called an apogee. In an apogee, the moon is 30,000 further away from this point.

According to NASA scientists, this weekend's super moon will appear 14 percent larger and 30 percent brighter than a regular full moon.