Why is it in news?

A rare total lunar eclipse that involves the second full moon of the month- popularly refered to as the ‘blue moon’- is set to take place on Jan 31^st for the first time in 150 years.

Details

• There are two definitions of a Blue Moon in astronomy; both are a type of Full Moon. If the moon actually looks blue, it's caused by a rare type of dust in the atmosphere.
• In astronomy, a Blue Moon is a Full Moon, which doesn't quite fit in with the months in our calendar. However, there are two completely different ways of calculating which Full Moon the odd one out, the Blue Moon.
• Blue Moon : The third Full Moon in an astronomical season with four Full Moons (versus the usual three)
• Blue Moon: the second Full Moon in a month with two Full Moons.
• Blue Moons can vary by time zone.
• The duration of the total phase is 77 minutes, with the moon tracking through the southern part of the earth’s shadow.
• The next similar events ould be on Dec 31, 2028 and Jan 31, 2037.

Source: The Hindu, timeanddate.com