Thomas Kast sent SPACE.com this photo of a lunar fog bow taken over a lake in Yli-Ii, Finland on Aug. 25.
Credit: © Thomas Kast, All Rights Reserved | Salamapaja
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.