The concept of rainbows is a pretty common one across the globe. But have you ever heard of a moon bow? Or a moon rainbow? Produced by moonlight as opposed to direct sunlight, a moonbow is a unique phenomenon. A naturally occurring atmospheric phenomenon, a moonbow is also known with various other names such as a lunar rainbow or sometimes even a white rainbow.
Although moon bows are also caused by refraction of light in water droplets, they are much fainter than their day counterparts. And that is due to smaller amount of light being reflected from the surface of the moon. This eventually leads to the colours being fainter, and it becomes difficult for the onlookers to differentiate between the colours. More often than not moon bows start appearing white and hence their name.
A moonbow or the lunar rainbow occurs and is fully visible in the night sky, when there is a full moon and the sky is a clear one with no surrounding clouds. A lunar rainbow also always occurs in the night sky in the opposite part to the moon. Generally, one will always spot a moonbow near a waterfall. As the waterfall will create a thin layer of mist making the sighting of a lunar rainbow possible. This phenomenon is also a delight for photographers as they can fully capture a moonbow, with all its visible colours with a long exposure in photographs.
One of the most revered places to witness a moonbow are the Victoria falls. One can enter via the Zambian or the Zimbabwean rain forest during a full moon. Every time during the full moon the rainforest opens its doors for a special tour during the evening for travellers to witness the moon bow or the lunar rainbow.
And if you’re wondering what time is the best to witness the phenomenon, the months of June, July and August are the answer. The prerequisites to witness a lunar rainbow in all its glory not only include a full moon and clear skies but also sufficient rising spray to refract the moonlight. A lunar rainbow is also best observed when the moon is low and near to full — at its brightest.
Previously the Niagara Falls also were home to this unique phenomenon but now due to development of the area around it has created light pollution and a lunar rainbow is no longer visible there anymore. There are other places also where one can witness this phenomenon including the Wallaman Falls in Australia, the Yosemite Falls in California, the Kihei Falls in Hawaii amidst other places.