Rainbows
Rainbows can be observed whenever there are water drops in the air and daylight shining from behind a person at a low height or angle. The most fabulous rainbow displays happen when half of the sky is still dark with draining clouds and the viewer is at a spot with clear sky in the direction of the Sun. The result is a incandescent rainbow that contrasts with the darkened background.
The rainbow effect is also commonly seen near waterfalls or fountains. Rainbow fringes can sometimes be seen at the edges of backlit clouds and as vertical bands in distant rain or virga. The effect can also be synthetically created by dispersing water droplets into the air during a sunny day. seldom, a moonbow, lunar rainbow or night-time rainbow, can be seen on strongly moonlit nights. As human visual sensitivity for colour is poor in low light, moonbows are often perceived to be white.
You can create your own rainbow by facing 180 degrees from the sun and spraying mist from a garden hose in front of you in a circular motion, outlining a 360 degree "rainbow".
It is difficult to photograph the complete arc of a rainbow, as this would require an angle of view of 84°. For a 35 mm camera, a lens with a focal length of 19 mm or less would be required, whilst most photographers are only likely to have a 28 mm wide-angle lens. From an aeroplane, one has the opportunity to see the whole circle of the rainbow, with the plane's shadow in the centre. This incident can be confused with the glory, but a glory is usually much smaller, covering only 5°–20°.
The rainbow effect is also commonly seen near waterfalls or fountains. Rainbow fringes can sometimes be seen at the edges of backlit clouds and as vertical bands in distant rain or virga. The effect can also be synthetically created by dispersing water droplets into the air during a sunny day. seldom, a moonbow, lunar rainbow or night-time rainbow, can be seen on strongly moonlit nights. As human visual sensitivity for colour is poor in low light, moonbows are often perceived to be white.
You can create your own rainbow by facing 180 degrees from the sun and spraying mist from a garden hose in front of you in a circular motion, outlining a 360 degree "rainbow".
It is difficult to photograph the complete arc of a rainbow, as this would require an angle of view of 84°. For a 35 mm camera, a lens with a focal length of 19 mm or less would be required, whilst most photographers are only likely to have a 28 mm wide-angle lens. From an aeroplane, one has the opportunity to see the whole circle of the rainbow, with the plane's shadow in the centre. This incident can be confused with the glory, but a glory is usually much smaller, covering only 5°–20°.
posted by computer at 8:10 AM
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