Just when you think the magnificent Victoria Falls has nothing more to offer than its sheer awesomeness. Few places in the world frequently feature spray moonbows, but Victoria Falls doesn’t give it up every night.
A moonbow (also known as a lunar rainbow, black rainbow, white rainbow, lunar bow, or space rainbow) is a rainbow produced by light reflected off the surface of the moon (rather than from direct sunlight) refracting off of moisture in the air (ever-present from the spray of the Falls).
Moonbows are relatively faint, due to the smaller amount of light reflected from the surface of the moon. They are always in the opposite part of the sky from the moon.
Because the light is usually too faint to excite the cone colour receptors in human eyes, it is difficult for the human eye to discern colours in a moonbow. As a result, they often appear to be white. So in fact the tones of the moonbow are from white to black whereas a rainbow has different variants of colour. However, the colours in a moonbow do appear in long exposure photographs.
A true moonbow is lit by reflected light from the Moon, not directly by the sun. In contrast, a coloured rainbow (or a white fogbow) seen when the sun is rising or setting, or in twilight,is not a moonbow because it’s still produced by sunlight.
|Fast facts about Moonbows:|
|Other common names for moonbow||Lunar rainbow, black/white rainbow, space rainbow|
|Best time to see a moonbow||Full moon, a lot of moisture in the air|
|How is it produced||Reflected off the surface of the moon refracting off of the moisture in the air|
|Colour of a moonbow||Tend to look black-white rather than coloured, but photograpghs bring out the colour|
|Best months to view a moonbow in Victoria Falls||February to July|
|Moonbows other than waterfalls or sprays||Moon needs to be less than 42 degrees and the sky very dark|
A coloured circle around the moon is not a moonbow, it is usually a 22° halo produced by refraction through hexagonal ice crystals in cirrus cloud. Coloured rings close to the moon are a corona, a diffraction phenomenon produced by minuscule water droplets or ice crystals in clouds.
Moonbows are most easily viewed when the moon is near to full (when it is brightest). The best time to see a moonbow at Victoria Falls, is during full moon, at times of high water – the months of February to July. These months are ideal as clear skies are normal and the spray has subsided to a point where the Falls are visible, forming a moonbow, reputedly one of the most staggeringly beautiful natural phenomena on the planet.
For true moonbows, other than those produced by waterfalls or sprays, the moon must be low in the sky (less than 42 degrees and preferably lower) and the sky must be very dark. Since the sky is still light on a rising full moon, this means they can only be observed 2 to 3 hours before sunrise, a time with few observers. And, of course, there must be rain falling opposite the moon. This combination of requirements makes moonbows much rarer than rainbows produced by the sun.
Moonbows may also be visible when rain falls during full moonrise at extreme latitudes during the winter months, when the prevalence of the hours of darkness giving more opportunity for the phenomenon to be observed.
Victoria Falls, on the border between Zimbabwe & Zambia, is one of the few places on earth where this impressive sight occurs regularly.
Visit the Victoria Falls Parks Rainforest and enjoy a mystic unforgettable experience in a guided moonlight viewing tour of the Falls. For three nights each month (one on either side of the actual full moon date) the Rainforest is open for a dramatic lunar rainbow, a rare natural phenomenon produced by the moon.
The opening and closing times of the Victoria Falls Parks Rainforest during full moon are from 6:00am to 8:00pm where the optional tour is an hour long.
If you are lucky enough to be travelling in Southern Africa during the full moon (dates below), don’t miss the magical moonbow.
Lunar Rainbow Dates 2013
July 21, 22, 23
August 20, 21, 22
September 18, 19, 20
October 17, 18, 19
November 16, 17, 18
December 16, 17, 18
Lunar Rainbow Dates 2014
January 15, 16, 17
February 13, 14, 15
March 15, 16, 17
April 14, 15, 16
May 13, 14, 15
June 11, 12, 13
July 11, 12, 13
August 9, 10, 11
September 7, 8, 9
October 7, 8, 9
November 5, 6, 7
December 5, 6, 7
Victoria Falls & Zambezi National Parks
P. Bag 5925, Victoria Falls, Zimbabwe
Telephone: 00263 13 42294 or 0026344566
Date: 3 July 2013