Moon Halo: A Rare Astronomical Phenomenon

Filipinos' fascination with astronomical phenomena went alive last night, January 13, when a moon halo appeared on the night sky. It is not my habit to observe the night sky, but my attention was caught by people who look up. The halo motivated many people to instantly grab their smartphones and digital cameras to take pictures and share the images on social media.


According to superstition, moon rings portend storms but science has a better explanation. Technically known as the 22-degree halo, the phenomenon is caused by the refraction of light through the 60-degree apex angle of the hexagonal ice crystals in cirrus clouds is deflected twice leading to deviation angles ranging from 22 degrees to 50 degrees. The variation in the refraction results in an effect similar to that of the rainbow.