Coronas & Sun Dogs

Colorful Solar Corona over Himalayas in Nepal © Jeff Dai
Colorful Solar Corona over Himalayas in Nepal © Jeff Dai

What are those colorful rings around the Sun? This is an example of a corona visible only to Earth observers in the right place at the right time. Rings like this will sometimes appear when the Sun or Moon is seen through thin clouds. The effect is created by the quantum mechanical diffraction of light around individual, similarly sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths, each color diffracts differently. Solar Coronas are one of the few quantum color effects that can be easily seen with the unaided eye and differs from the solar corona that continuously exists around the Sun — and stands out during a total solar eclipse.

 

Lunar corona around a Strawberry Moon on June 2nd in Argentina © Sergio Montufar

Sun dogs are a member of a large family of halos, created by light interacting with ice crystals in the atmosphere. Sun dogs are best seen and are most conspicuous when the Sun is close to the horizon. They typically appear as two subtly colored patches of light to the left and right of the Sun, approximately 22° distant and at the same elevation above the horizon as the Sun.

Beautiful winter scenery with country under snow and a sun with halo circle called a Sun Dog. Photo from Kulfoto.com
Beautiful winter scenery with country under snow and a sun with halo circle called a Sun Dog. Photo from Kulfoto.com
Sun Dogs in South Dakota by Wayne Specht
Sun Dogs in South Dakota by Wayne Specht

 

 

 

 

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