Bad weather may affect visibility of rare blue moon

CEBU, Philippines - A rare blue moon will brighten the sky tonight at 6:43.

But the Philippine Atmospheric, Geophysical and Astronomical Services Administration said unfavorable weather conditions in Cebu and parts of Central Visayas may affect the blue moon’s visibility.

“Cloudy skies may affect the exceptional view of a blue moon or worse it couldn’t be seen,” said Alfredo “Al” Quiblat Jr., chief meteorological officer of PAGASA Mactan.

 Blue moon, Quiblat said, is the second of two full moons occurring in the same month. The first full moon this month occurred on July 2 at 10:20 a.m.

“Blue moon is an additional full moon that appears in a subdivision of a year, either the third of four full moons in a season or a second full moon in a month of the common calendar,” he added.

 Full moons occur every 29.530589 days, on average, which is the lunar synodic period.

 PAGASA clarified that the name does not reflect the actual color of the moon.

But there are instances when the moon actually appears to be blue such as during volcanic eruptions and occurrence of large fires that emit particles to the atmosphere.

According to the National Aeronautics and Space Administration website, a truly-blue Moon usually requires a volcanic eruption.

 One of this happened back in 1883, when the Indonesian volcano Krakatoa exploded with the force of a 100-megaton nuclear bomb. Plumes of ash rose to the Earth’s atmosphere and the volcanic debris caused the moon to have blush tint.

 People also saw blue-colored moons in 1983 after the eruption of the El Chichon volcano in Mexico. And there are reports of blue moons caused by Mt. St. Helens in 1980 and Mount Pinatubo in 1991.

 This lunar event will not be seen again until May 18, 2019 and August 22, 2021.  (FREEMAN)