Cheryl Swem (Member 65,007) stepped out onto her front yard in Oceanside, California, US to enjoy the cool early morning air when the sky brought her a separate joy. Around the Sun, she found subtly blended bands of iridescent hues. Cheryl had spotted a solar corona.

The effect is the result of sunlight bending, or diffracting, around the tiny supercooled droplets within the gentle waves of Cheryl’s Cirrocumulus undulatus cloud. Since different wavelengths of light bend by different amounts as they pass around a minuscule obstacle, each of the cloud’s particles would have made its own diffraction pattern, separating the sunlight into its constituent colours. The droplets must have all been of a very similar size for this effect to add up to the broad pattern of a corona.

‘I don’t have any fancy camera equipment,’ Cheryl told us, ‘so I just tried to shield my cell-phone lens a little from the light with the tree leaves.’