A rare sun-moon-and-Earth activity is working up a supermoon waiting to be presented into view from behind the Earth's blanket of stars and clouds. The supermoon will wow skywatchers come Sept. 27, and it will come with a twist.

Coincidentally, the Sept. 27 supermoon will also fall under a lunar eclipse. If you won't be able to see this spectacularly strange phenomenon as it happens end of this month, don't worry, there's always a next time - nearly two decades from now.

The moon revolves around the Earth which in turn revolves around the sun. The moon, however, does not have a perfectly circular orbit around the Earth, so during the whole cycle, the moon will be closest to the Earth at one point. When full or new moon's elliptical orbit takes it nearest to Earth, the moon appears larger in diameter by 14 percent. It also appears to be brighter by about 30 percent, as seen from Earth.

During a lunar eclipse, the moon, Earth and the sun are very closely aligned, if not exactly. The moon passes behind the Earth and in its umbra or shadow, making the Earth fall between the moon and the sun. Because of its reddish color, it has also been named "blood moon."

On Sept. 27, in a combination of these two phenomenon, the moon will fall directly behind the Earth in a lunar eclipse, giving it a red tint, and also appearing brighter and bigger as its orbit bring it closer to the planet.

After sunset on the 27th, the entire South America and majority of North America will be a witness to the rare supermoon lunar eclipse. In other parts of the world - Europe, Africa and the Middle East - it will also be visible from after midnight to before sunset. The last time a supermoon lunar eclipse was visible from Earth was in 1982, and after this year, it will come back in 2033.

Since the 1900s, the rare heavenly display has made appearances five times, actually every 18 years up until it was last seen - 1910, 1928, 1946, 1964 and 1982.

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