The Anna Science Centre-Planetarium in Tiruchi organised a special public viewing of the rare “Blue Moon” phenomenon on its premises on Sunday, attracting astronomy enthusiasts.

The public was given an opportunity to observe the full moon through telescopes arranged by the planetarium.

A blue moon is an astronomical and calendar-related phenomenon that occurs when a second full moon appears within the same calendar month. May witnessed a full moon on May 1, followed by another full moon on May 31, making the latter a blue moon.

Since a full lunar cycle takes approximately 29.5 days while most months have 30 or 31 days, an additional full moon occasionally occurs. The next blue moon may be on January 31, 2037, the project director said.

Visitors were informed about the much rarer “True Blue Moon”, a phenomenon in which the moon may appear bluish due to atmospheric conditions. Such occurrences can happen when large quantities of dust or smoke particles from volcanic eruptions, forest fires, or huge dust storms remain suspended in the atmosphere and scatter light in a particular way.

One of the most notable examples was observed following the eruption of the Krakatoa volcano in the year 1883.