At least two moonbows, including a stunning double moonbow, appeared in the skies of the United States as the blue supermoon rose.
Double moonbow in Colorado on August 18. (Photo: Aaron Watson)
Rare moonbows illuminated the night sky above the United States shortly before the blue supermoon reached its peak. Also known as a night rainbow, this phenomenon is created in a similar way to a regular rainbow but differs in that it appears when moonlight, rather than sunlight, is reflected and refracted through raindrops. However, they are much rarer because they can only be seen during a full moon, when Earth’s natural satellite is the brightest in the night sky, according to Live Science.
The moonlight is too faint compared to sunlight, causing moonbows to often appear white since the color-detecting receptors in the human eye do not function well in low-light conditions to differentiate the spectrum of colors, according to the UK Met Office. However, the moon has been unusually bright in recent days leading up to the blue supermoon, allowing for these moonbows to display more vibrant colors.
Astronomical photographer Aaron Watson spotted the double moonbow over Paonia, Colorado, at around 2 AM on August 18, as reported by Spaceweather.com. “The rainbow was so vivid that it was even visible to the naked eye and lasted for several minutes before slowly fading away,” Watson shared. Another moonbow was also observed the same night above Keuka Lake in New York. This moonbow was not as bright as the one in Colorado but still displayed several characteristic bands of color when captured on camera.
Although the moon will be less bright in the coming nights, experts say that moonbows can still occur when it rains, as long as the moonlight can refract through raindrops. Additionally, this phenomenon can only be seen when the light source is the moon positioned behind the observer. The colors of the moonbow may appear more distinct in photographs since cameras can capture the subtle colors that the human eye may miss.
