Have you ever encountered a rainbow-like patch near the sun? Or maybe more than one sun? If you plan to hang out on winter afternoons or early sunset during the hot summer you might get a chance to see sundogs. Sundogs are bright spots in the sky appearing on either side of the sun or rainbow-like patches near the sun. They are also known as “mock suns” or “parhelia,” which means “with the Sun”. They are an atmospheric optical phenomenon that is a member of the family of halos.
Sundogs are formed by hexagonal ice crystals present in clouds that are in the air at lower levels. These ice crystals sink vertically through the air and act as a prism which lets the light rays get refracted. Sun rays enter one side of the crystal and pass through another, inclined at 60 degrees to the first surface. The angle of deviation of the rays is 22° or more. The distance between the sun dog and the sun affects the colour of the sun dog. Red is the least deviated colour which often gives the sun dogs a red inner edge. Farther out, the colours fade from shades of orange to blue. Usually, the colours overlap and result in varying shades of white. But what determines the type of these sundogs? The shape of the crystals determines the form of sun dogs. They can appear as broken fragments of a rainbow or entirely another sun(s). Clear and visible sun dogs occur when the horizon is close to the sun. As the sun rises, the sun dogs begin to fade, since the rays passing through the ice crystals are skewed and the angle of deviation increases. Could you ever imagine something as meagre as ice crystals could create such wonders?
Sundogs are not a useless phenomenon. It indicates that rain is on its way with foul or wet weather on the horizon within the next 24 hours. It was also believed in medieval times that the three bright lights were a sign of great fortune. Nowadays, seeing a sundog is just an opportunity to decorate your story on social media or maybe it might be a sign of good luck for you too!
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