Once in a blue moon: How to see the two supermoons appearing in August

Credit: AP

The cosmos is offering up a double feature in August, a pair of supermoons culminating in a rare blue moon.

A glimpse of the first supermoon can be caught on Tuesday evening as the full moon rises in the southeast, appearing brighter and bigger than usual.

This is because it will be closer than usual, just 222,159 miles (357,530 kilometres) away, thus the supermoon label.

The moon will be even closer the night of August 30, a mere 222,043 miles (357,344 kilometres) away.

As it’s the second full moon in the same month, it will be called a blue moon, and as the saying goes, the night sky phenomenon is pretty rare.

“Warm summer nights are the ideal time to watch the full moon rise in the eastern sky within minutes of sunset. And it happens twice in August,” said retired NASA astrophysicist Fred Espenak, dubbed Mr Eclipse for his eclipse-chasing expertise.

The last time two full supermoons graced the sky in the same month was in 2018.

It won’t happen again until 2037, according to Italian astronomer Gianluca Masi, founder of the Virtual Telescope Project.

Masi will provide a live webcast of Tuesday evening’s supermoon, as it rises over the Coliseum in Rome.

“My plans are to capture the beauty of this ... hopefully bringing the emotion of the show to our viewers,” Masi said.

“The supermoon offers us a great opportunity to look up and discover the sky,” he added.

What is a Supermoon?

A Supermoon is when the moon appears a little bit bigger and brighter in the sky.

As the moon goes around the Earth, there are points in its orbit in its Full Moon phase where it is slightly closer to Earth, known as its 'perigee': around 360,000 km away and 22,000 km closer.

It means it looks a little larger and more vivid to the naked eye.

When the moon viewed near the horizon looks larger than usual, your brain is playing a trick on you - it’s called the moon illusion.

This year’s first supermoon was in July. The fourth and last will be in September. The two in August will be closer than either of those.

Provided skies are clear, binoculars or backyard telescopes can enhance the experience, Espenak said, revealing such features as lunar maria - the dark plains formed by ancient volcanic lava flows - and rays emanating from lunar craters.

According to the Old Farmer’s Almanac, the August full moon is traditionally known as the sturgeon moon. That’s because of the abundance of that fish in the Great Lakes in August, hundreds of years ago.

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