New Delhi, Dec 29 (IANS) Take out some time from new year eve revelry Thursday and look at the sky to catch a glimpse of a rare celestial phenomenon - a blue moon. A partial lunar eclipse will also be observed early Jan 1, 2010.
The full moon on Thursday will be a “blue moon”.

A blue moon has nothing to do with the colour of the moon but when two full moons occur within the same month, the second full moon of the month is called a “blue moon”, a term used metaphorically to describe the rarity of an event, as in the idiomatic expression — once in a blue moon.

“Most years have twelve full moons, but since a lunar cycle is 29.5 days, we wind up with almost 11 leftover days. Eventually the days add up, and we have two full moons in a single month — like we do this month,” said N. Rathnasree, director of the Nehru Planetarium here.

A blue moon comes every two-and-a-half years on an average, but this will be the first time since 1990 that it will coincide with new year’s eve. The event will not happen again till 2028.

The lunar eclipse will begin at 12.22 a.m. and end at 1.24 a.m. Friday. However, the partial eclipse will not be visible with the naked eye, Rathnasree said.