Christmas will come early for Australia's budding astronomers, with not one but two space spectacles scheduled for Friday night.
The Christmas Comet and the Geminid meteor shower are due to light up the night sky within just hours of one another.
The Christmas Comet - which is named for the time of year it appears - is expected to emerge from 9pm AEDT as a green and fuzzy comet in the east, close to the constellation known as Orion, or the Saucepan, ANU astronomer Dr Brad Tucker said.
"The green colour is coming from the gas that is coming off the comet," he told AAP.
"There is a bunch of ice on it and methane - it's essentially like a dirty snowball and so when it goes around the sun it melts ... and is a steamy, stinky green glow."
This will be rare chance for Australians will have to catch a glimpse of the comet, which appears only once every five years.
Hours later shooting stars are set to flash across the sky as Earth passes through the tail of the 3200 Phaethon asteroid.
They'll look impressive from the ground but the falling stars are actually just small rocks that have broken off from the asteroid before burning up in the Earth's atmosphere.
"They're about the size of a grain of sand, or even a small pebble and they're travelling tens of thousands of kilometres an hour," Dr Tucker said.
While observers will need a pair of binoculars or a telescope to catch the Christmas Comet, the meteor shower will be visible from anywhere in Australia, even major cities, so long as it's a clear night.
"It's very accessible, you don't need anything special, you just need the night sky," Dr Tucker said.
