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Get ready for Saturday's supermoon, astronomy fans

Fans watch the Egyptian Super Cup soccer match during a full moon at Cairo Stadium July 25, 2010.

© Amr Dalsh / Reuters/Reuters

Parents, go on, let your children stay up a little later Saturday night. Grab the blankets, set out the lawn chairs and enjoy the glow of the supermoon – if you can.

A supermoon occurs when a full moon is also at its perigee, its closest point to Earth on its elliptical path. On May 5, at 11:34 p.m. ET, it will reach this perigee point, and one minute later, will line up with the Earth and the sun to appear especially big and bright.

"The timing is almost perfect," NASA's Science News site says, noting that Saturday's supermoon will be as much as 14 per cent bigger and 30 per cent brighter than any other full moon this year.

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But don't feel bad if you don't notice a difference. Eric Briggs, secretary of the Royal Astronomical Society of Canada's Toronto centre, says the supermoon will look pretty much the same as other full moons; the fact that it's a few thousand kilometres closer will be imperceptible to casual sky-gazers. He suggests comparing photos of the moon taken at its closest and furthest points from Earth to get a better sense of the effect.

Still, it's expected to be beautiful, says Cam Cronin, public programmer at Vancouver's H.R. MacMillan Space Centre. "It's a lovely opportunity to take in the beauty of the moon and to take pictures, if the weather is favourable."

NASA says supermoons happen, on average, roughly once a year.

The moon does have an illusion of being bigger when it's hovering just above the horizon. That means Saturday's moon may seem particularly large around sunset, just after it rises, Mr. Briggs says.

Good news, if your children struggle to stay awake past nightfall.

Ready, set, shoot: E-mail us your best photos of the supermoon. Include as much information as you can (your name and city, location, and anyone in the photo.)

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