Spectacular light display in Manitoba

21st February 2020 Last updated at 11:01
Moon dogs and halos in Manitoba
Brent McKean
Moon dogs and halos in Manitoba

Canadian photographer Brent McKean took this stunning shot in Manitoba on 13th February.

There's a 22 degree halo with "moon-dogs", the upper half of a circumscribed halo above the moon, a hint of a light pillar below the moon, and a diffraction corona around the moon itself.

The halos are from the refraction of light by ice crystals in the shape of hexagonal prisms (the circumscribed halo above the moon is due to the moon's low angle in the sky). The moon-dogs indicate that the crystals are vertically aligned. The diffraction corona around the moon is caused by light getting bent around and between water droplets, in this case super-cooled ones. So here the moonlight is travelling through two layers of particles, one higher aloft with frozen ice crystals, and another at a lower level with super-cooled water and no ice present. This water layer would also need to be away from the surface a bit, as pollutants or salts in the air will cause the super-cooled water to freeze.