Tips for finding and capturing the lunar fog bow

A month ago I had never seen a lunar fog bow, now I have seen three. I got to see my first lunar fog bow on December 17 last year. Last night I got to see two more of these elusive phenomena. We had lots of fog around the city of Östersund and since it was the night of the full moon, I drove around chasing locations where I could see these beautiful bows.

I got two relatively good ones on photo two hours apart. I’ve included the time and height of the Moon when the photos was taken.

This is something I really love with this type of photography, learning about new phenomena and how and when to see them. After seeing my first lunar fog bow I knew how it looked like and what conditions to look for. Last night there where perfect fog bow conditions so it was just a matter of finding the right spot. The moon light needs to be bright so the days around full moon is best. Also the light from the moon can’t be to obscured by the fog and you need to have rather dense fog in the opposite direction of the moon. So try to find a location where you’re standing just beneath the top of the fog, then you are inside the fog but the moon light is still bright enough to light up the bow.

Also, as you can see by these two photos, a lunar fog bow works exactly as a rainbow, the height of the bow is determined by the height of the light source (Sun/Moon), so if the moon is too high in the sky > ~35° the fog bow won’t be visible. A rainbow has a radius of 42° so if the Sun’s altitude in the sky is more than 42°, a rainbow can’t be visible. The same goes for a fog bow, but it has a much broader radius, 30-45°. So, the lower the altitude of the Sun/moon is, the higher the bow is.

Good luck bow hunting!

About the Author

Göran Strand is a  professional photographer from Östersund, Sweden, focused mainly on astrophotography. You can see more of his work on his website, follow him on Twitter and Instagram, or like his Facebook page. This article is also published here and shared with permission.