My geological engineer/exploration geologist daughter Évelyne captured this image of solar halo in Catalonia, Spain. Solar halo is an atmospheric optical phenomenon appearing as a bright ring, roughly 22 degrees in radius, around the Sun. It occurs when sunlight refracts through millions of hexagonal ice crystals suspended in high-altitude cirrus or cirrostratus clouds. These crystals act like prisms, often creating a coloured (red-inner, blue-outer) or whitish ring.
