Hong Kong on Tuesday witnessed a rare natural phenomenon, a halo around the sun, that can be experienced ... radius of 22 degrees, with a pale red lining or a purple aura at times.

PETOSKEY — If you look up at the sky on a sunny day, a glowing ring could be visible around the sun under certain conditions. That bright, circular halo is a natural optical phenomenon known as ...

A halo will form around the sun when this same process occurs during daytime hours. Unlike rings around the moon, solar halos exhibit more of a red hue inside their ring and blue outside it.

A small halo has an angular radius of 20 degrees, with a pale red lining or a purple aura at ... "Remember not to look at the sun directly, as strong sunlight can cause blindness," she said.