The ethereal light of a lunar fog bow made of moonlight and fog glows over a Finland lake in this beautiful night sky photo.
Finnish photographer Thomas Kast took this stunning shot on a cold, foggy night around 1 a.m. local time on Aug. 25, from Yli-Ii, Finland.
"This lake remained clear for a long time. At one point I saw this white bow with the waning gibbous behind me. I had no clue what it was that I saw and started to take pictures," Kast wrote SPACE.com in an email.
Similar to a rainbow, tiny water droplets that cause fog reflect light. Lunar fog bows typically appear white because sunlight reflected from the moon is weak.Some photographers have also captured so-called "moonbows ," which are similar to rainbows in that they do include colors.
The lunar fog bows lack of colors is caused by the smaller water drops … so small that the wavelength of light becomes important. Diffraction smears out colors that would be created by larger water drops in rainbows , according to NASA.
To see more amazing night sky photos submitted by SPACE.com readers, visit our astrophotography archive .