Ring Around the Moon

The otherworldliness of this image, obtained at ESO’s Very Large Telescope (VLT) in northern Chile, is due to a combination of natural and artificial light phenomena. This ethereal image captures a lunar halo on rare cloudy skies over ESO’s Paranal Observatory. This optical phenomenon is created when moonlight is refracted by millions of small ice crystals and water droplets in the surrounding atmosphere. 

These haloes are reasonably common; however, they require quite a bit of light to appear, so the Moon must be in a specific position relative to the Earth and the Sun to reflect enough light to produce a fine ring like this one. This particular halo comprises multiple coloured bands that are formed in the same way as in a rainbow — light of different wavelengths is refracted by varying amounts. White light is thus broken into its constituent parts, dispersing to create a spectrum of visually distinct colours.