This is one event that never ceases to excite astronomers around the world, who would focus their telescopes skywards on January 31 to view the rare ’Super Blue Blood Moon’.

The excitement will be double this time as the supermoon, blue moon and blood moon will merge together after a period of 150 years.

Pramod Galgali, director of Jawaharlal Nehru Planetarium, however, clarifies that the term ’supermoon’ was coined only in the last decade and is not a scientific phenomenon. The same can be said about blue moon, which is neither scientific nor rare.

"January 31 will nonetheless be special since the moon would rise when it is in total eclipse," Galgali said. "It will totally be under the earth’s shadow and a rare sight."  

A partial lunar eclipse occurs when the moon passes through the lighter part of the earth’s shadow, called penumbra. While it may go unnoticed, it is hard to miss the total eclipse that occurs when the moon enters the darker part of the shadow called umbra.

At this stage, the moon gets a reddish tinge since the earth blocks sunlight from falling over its surface and the moon is lit up by the earth’s atmosphere. This is why the moon is called ’red moon’.

On January 31, the moon will enter the penumbra at 4.20 pm and the umbra at 5.20 pm. "But the moon will rise in Bengaluru only at 6.15 pm. By this time, it will be fully eclipsed," Galgali said. The moon will exit the umbra by 8.40 pm and the eclipse will end by 9.40 pm.

The red moon can be seen clearly from the top of a hill or a building. The view will be better with a binocular or telescope. Unlike the solar eclipse, lunar eclipses do not affect the eyes and can therefore be seen with naked eyes.

While trees and buildings around the planetarium will impede viewing of the moon rising, it can, however, be seen after the rise. "Anyone can come here and view the red moon for free with our binoculars and telescopes," Galgali said, adding that it would accommodate people on first-come-first-served basis.

The department of public instruction has issued a circular, urging teachers in all schools across the state to encourage students and parents to view the phenomenon.