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Giant crimson moon on the rise

A supermoon viewed from Spain in January 2018 REUTERS/Eloy Alonso

People in east Asia, Oceania and the Americas will be able to witness a giant crimson moon on Wednesday, thanks to a rare lunar trifecta that combines a blue moon, a super moon and a total eclipse for the first time since 1982.

The phenomenon, which the US's Nasa has dubbed a "super blue blood moon", will be visible before dawn in the western United States, as the moon crosses into the shadow of the Earth and turns blood red.

The last time a supermoon and a total lunar eclipse coincided was in 1982, Erwan Mazarico, geophysicist at Nasa's Goddard Space Flight Center outside Washington DC told RFI.

"Each aspect is not unusual in itself but the combination of them is," he said,  adding that the last time the total ccombination was noted was in 1844.

People will be able to view the crimson moon in full across east Asia, Australia, Alaska, Canada, and the West of the United States just after dawn.

Nasa is streaming the event live - an opportunity that will not occur again before 31 January 2037.

A super moon occurs when the moon, in its elliptical orbit, is near its closest point to Earth.

This proximity, or perigee, makes it appear 14 percent bigger than normal and 30 percent brighter.

The reddish tint -- or blood moon -- happens due to "the effect of all the sunrises and sunsets all around the planet reflecting off the moon, which I think is really lovely," said Nasa astrophysicist Michelle Thaller.

"The reason a sunrise or a sunset is red is the sunlight has to pass through a large amount of air on the side of the Earth and that actually scatters away any blue light and just lets the red light come on through," she said.