While in Yosemite this summer, we caught wind of the moonbow phenomenon. We had no idea it was a thing, and we just happened to be at the right place and at the right time when the moonbow was occurring. We felt extremely lucky to witness this rare phenomenon, especially when so many people plan trips out here with no guarantee if it will show up. Ever since seeing our first moonbow, we’ve been obsessed with seeing them all (maybe it’s more me than Jacob).
“Lunar rainbows or spray-bows abound in the glorious affluence of dashing, rejoicing, hurrahing, enthusiastic spring floods, their colors are distinct as those of the sun and regularly and obviously banded, though less vivid. Fine specimens may be found any night at the foot of the Upper Yosemite Fall, glowing gloriously amid the gloomy shadows and thundering waters, whenever there is plenty of moonlight and spray.” – John Muir at Yosemite Falls
What is a Moonbow?
Moonbows are rainbows caused by the moon instead of the sun. They are rarer than rainbows because the weather and astronomical conditions have to be perfect.
What Causes a Moonbow?
Just like rainbows in the day, the water droplets have to be at the correct angle opposite the direction of the light source to reflect, refract, and disperse the light. Sounds simple enough, but there are a lot of factors.
- The sky needs to be clear or relatively clear
- It needs to be a full moon or near full moon.
- No other bright light source can be present.
- There needs to be sufficient mist. Moonbows are more frequent in some parts of the world where the waterfall is creating a lot of mist, while other parts, they only occur in spring when enough water if flowing.
- There needs to be enough wind and in the right direction to pick up the mist.
What Does It Look Like to the Naked Eye?
Moonbows look more like a white or silver streak to the human eye. You will see the shape of the bow, but the colors just aren’t bright enough for our eyes to see. That’s where the magic of photography comes in!
Here are the places where you can find moonbows:
Moonbow Locations Around the World
- Upper & Lower Yosemite Falls, Yosemite National Park, California (watch from the foot of either upper or lower falls)
- Cumberland Falls, Kentucky (watch from behind the railing at the upper overlook area)
- Victoria Falls, Zambia / Zimbabwe
- Waimea Canyon State Park, Hawaii
- Skogafoss Waterfall, Iceland
- Wallaman Falls, Australia
- Jerome, Arizona
Not all the locations have predictions put together, but if you plan on visiting Yosemite National Park, check out this site for predictions on dates and times! At Cumberland Falls, there’s a chance it shows up every month around the full moon as long as all the other conditions are right.
- Start by using settings you would use to shoot night photography. My settings were 35mm, ISO 500, 8 sec, f/1.6.
- Adjust accordingly based on how bright or faint the moonbow and surroundings are.
- Your lens will get wet from the mist. Bring several lens cloths to wipe your lens in between shots (you might also want to bring a raincoat if it’s really misty).
- If you’re unsure if you see it, just take a photo and see!
- You’ll be taking a long exposure. Use a tripod and remote shutter release.
- Bring extra batteries. Long exposure will eat up those batteries.
- Bring headlamps with a red light feature. There were a ton of other photographers out that night and a few of them kept turning on their headlamps super bright, which ruined other people’s shots.
- Practice! Spend some time just shooting the night sky to get a hang of your settings. It’s better that you have a general idea so you can move quickly when you get a chance to shoot the Moonbow.
- Get a rain cover for your camera (especially if it isn’t weather sealed!). Here’s a relatively cheap one that we use.
Have you heard about the moonbow phenomenon? Which one of these are you going to visit first / next?