A blue moon will be visible on New Year's Eve this year, adding to the merriment of New Year celebrations. This time the blue moon would be visible after a 20 year gap.
A blue moon - the second full moon in a calendar month - happens only every 2 and half years on average.
According to a report in The Age, there will be a blue moon on Thursday, December 31, as New Year's Eve revellers welcome in 2010.
This would be the first time since 1990 that a blue moon has coincided with the end of the year.
Astronomer David Reneke from Australasian Science magazine said it was rare for the event to happen on New Year's Eve.
Another blue moon will not fall on the last day of the year until 2028.
"'While everyone's celebrating, they should also take a moment and look up into the night sky," Reneke said.
The event has an added significance, as it comes just months after the world celebrated the 40th anniversary of man landing on the moon in July.
"What a great finish to the year," Reneke said. "We haven't been up there since 1972, so it's a good time to have a look and wonder what the decades to come will bring," he added.
But the moon won't turn blue.
If anything, Reneke said it could turn red when viewed from cities because of the filter effect of smoke from fireworks.
"It's not impossible that the fireworks will change the colour of the moon," he said.
The phrase "blue moon" has become a metaphor for a rare event.