Rare 'Blue Moon' to be visible on August 31 night

A rare 'Blue Moon' awaits sky aficionados on Friday night.

When a second full moon in a calendar month appears in the night sky, the occurrence is known as a 'Blue Moon'.

This month, the first full moon was on August 2 and now, sky gazers can see it happening for the second time on Friday night at 19:28 pm, N Sri Raghunandan Kumar, Director Planetary Society of India said.

The second full moon of any month is referred as a 'Blue Moon' as it happens rarely.

The next 'Blue Moon' will occur only after three years on July 31, 2015.

On rare occasions, the moon actually has a blue appearance - often caused by smoke from large-scale fires or excessive dust particles in the atmosphere, Science Popularisation Association of Communicators and Educators (SPACE) president C B Devgun said.

Explaining the phenomena of blue moon, Devgun said the moon cycle takes about 29.53 days to complete that is almost a month. That is why there is one full moon once a month, but a 'Blue Moon' happens once in every two and a half years on an average.

The moon will rise at 6.13 PM and will reach its fully illuminated total phase at 7.28 pm, Kumar said.

The last time 'Blue Moon' event occurred in December, 2009.