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   Ice Crystal Halos 


Ice halo displays range from the familiar circle around the sun or moon to rare and prized events when the whole sky is webbed by intricate arcs.

Tiny ice crystals in the atmosphere create halos by refracting and reflecting light.

Halos bestow a delicate beauty to the skies and tell us about the crystals inhabiting the clouds.

Find out how halos are formed, when and where to see them in the skies.

Create your own halo displays by downloading the full colour simulator program, HaloSim.


  A circular 22° halo surrounds a low sun. To the left and right are sundogs. Above shines an upper tangent arc and beneath is a sun pillar. HaloSim simulation of halos frequently visible in the sky.