Moonbow

A moonbow (also known as a moon rainbow or lunar rainbow) is a rainbow produced by moonlight rather than direct sunlight. It forms in much the same way as a regular rainbow, when light bends through many tiny water droplets, such as those in a rain shower or near a waterfall. The moonbow always appears opposite the Moon in the sky from where you are standing.

Moonbows are much softer and lighter than regular rainbows because the Moon gives off far less light than the Sun. This makes it hard for our eyes to see the colors in a moonbow, so it often looks white to us. However, if you take a long picture with a camera, the colors of a moonbow can show up in the photograph.

People have talked about moonbows for a very long time. They were written about by the ancient Greek thinker Aristotle in his book Meteorology around 350 BC. Moonbows were also linked to Selene, the ancient Greek goddess of the Moon, Selene.

Viewing

Moonbows are easiest to see when the Moon is very bright, like during a full moon. The Moon needs to be low in the sky and not covered by clouds. The sky also needs to be very dark, which usually happens a few hours before sunrise or after sunset. There must be water droplets, like from rain or spray, opposite the Moon. Because of all these conditions, moonbows are much rarer than regular rainbows.

The colours of a moonbow can change depending on the size of the water droplets. Smaller droplets usually make the colours less vivid.

Locations

Moonbows can be seen in many places around the world. In the United States, they appear near waterfalls such as Niagara Falls in New York, Yosemite National Park in California, and Cumberland Falls near Corbin, Kentucky. Victoria Falls, on the border between Zambia and Zimbabwe, is also famous for moonbows.

In Costa Rica, moonbows are often seen in the cloud forests of places like Monteverde and Santa Elena. These happen when misty clouds blow in from the Caribbean during a certain time of year. Moonbows in this area occur almost every full moon from December through February.

Moonbows are also found in wet areas of Hawaii, such as Kauai and the Big Island of Hawaii.