THREE THINGS ABOUT SUN HALOS
Southern Ontarians, especially the province’s meteorologists, were delighted to capture the optical phenomenon known as a sun halo on Monday afternoon. Here are three things to know about them.
1 THE SUN’S LIGHT PASSES THROUGH ICE CRYSTALS
Sun halos are composed of a range of different optical phenomena, all caused by light from the sun passing through cirrus clouds, which comprise millions of ice crystals. These phenomena can appear for the moon as well, but they are rarer, less pronounced and harder to notice. The different permutations of light passing through the ice, as well as the orientation of the viewer, are what creates the optical effects like the one seen in Ontario on Monday. The halo appears as a circle around the sun with a radius of around
22 degrees.
2 HALOS, DOGS AND LIGHT PILLARS
Sun halo, sun dog or a light pillar: What are the different members of the sun halo family? A sun dog, also known as a parhelion or a mock sun, develops alongside a 22-degree halo and appears as
colourful spots of light on the left and/or right edge of the halo. Light pillars appear separately from the 22-degree halo and feature pillars of light shooting up into the sky, making for some
fantastic photos. Similar to sun halos and sun dogs, light pillars form due to light passing through ice crystals in the atmosphere. Where light pillars differ, however,
is that they do not require light from the sun to form, but, for example, develop as city lights interact with ice crystals on a
cold winter night.
3 TAKE PRECAUTIONS WHEN VIEWING
While data around the frequency of sun halos is not typically collected, they are not rare and if you spend enough time outside, one is certain to appear eventually. However, the issue with sun
halos is not finding them, it’s viewing them safely. Whenever you’d like to look at the sun,
make sure you take proper precautions to make sure you do not cause damage to your eyes, as even looking at the sun for a short period of time can be potentially harmful.