RAINBOWS & PRISMS

Spring time in the Peak district, big sky's sunshine & showers  a perfect mix for
Rainbow chasing. Ashbourne was the starting point then on to
the Manifold Valley via the village of Grindon.
Parking at Weags Bridge along the Manifold way, heavy rain was
hammering down, so a flask of tea made an appearance
and i waited till this large shower ran out of steam.
A Year earlier I had missed a bright Rainbow upon the Larkstone lane,They
sometimes only last a few minutes, not enough time to set up
a tripod and camera. So armed with weather information
and the fact that it was April and it was very showery, my timing was spot-on.

I am always conscious of how much petrol it takes to get me to my
destination, both in cost and the environment, so it has sharpened my
ability to plan & time my many trips to all over the UK.

Here we go, it's stopped raining now so off i trek, up the Road I had driven down,
not far up the hill the brolly came out and down it poured, a rivulet ran down the
 side of the lane. I thought:

"Have i arrived on the wrong day?"

So now I am thinking, this rain is not letting up, but as i reach the top of the lane
the rain slows, I'm not heading back down the Lane, so i climb the stile, over the
right of way and get set up. Forty five minutes and the sun showed his face and
the rain and hail continued to pour, a Rainbow appeared right in front of my
view, right opposite "Larkstone Lane".

 The rain lasted long enough for me to get a number of images, in the
original image you can make out a second fainter Rainbow, and in this
next image you can see the hail raining down through the Rainbow!!
I worked out that the rainbow was only 350 meters from my camera,
hence the image only contains a small part of the
Rainbow's Arc, it would have taken a super wide angle
lens, to get the entire arc in the image,
or a much further distance, and that's part of the problem
the rain in front of you can be a few meters or miles
away, nature and luck plays it's hand.
In the left of the above Image shows the darker area of sky called
"Alexanders Band", it is darker due to the formation of
a secondary Rainbow above the main primary Rainbow.
See HERE for a more detailed photo.

Click on the Hailstones Image above to enlarge it!.

Below is my poor drawing and novice explanation
of how a Rainbow is formed in the rain drops, my example
is a typical double rainbow, once you understand
the principle of dispersion of the sun light
the magic is shattered, but not the wonder. if my
explanation is wrong, then tell me and I will amend.


1. Light enters the Rain drop at (B) and is refracted..............................
2. From the surface of (B) it is refracted down to (C).............................
  3. From (c) the light is again refracted down to(D)..................................
 4. The light is now fully split into it's different wave lengths.................
 5. Dispersion is the term used, for the final exit out of the rain drop..
 You should now see all the colours of the Rainbow...........................

 A Rene Descartes style sketch

The primary Rainbow you see in the drawing is the lower arc,the

secondary is the upper Rainbow, or second Rainbow you sometimes see

if you see two Rainbows then note the upper one will

appear mirrored and often looks upside down.

If you look at the drawing again, and follow the secondary light ray

you will see it travels from A2 and strikes the bottom

of the rain drop at B2, and so on until it exits at E2.

The primary Rainbow; Light enters at (B) into the rain drop and 

is refracted clockwise round to (D), but............

The secondary Rainbow; Light enters at (B2) into the rain drop 

and is refracted anticlockwise round to (E2).

The clockwise and anticlockwise does explain to (me) why we

see the secondary Rainbow as an upside down Rainbow.

Well that's the best i can do for an explanation as to how a Rainbow 

is observed.

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The next day I returned to try other areas of the Peak district,
bands of showers were still forecast, so there was
a good chance I would see more Rainbows.
Traveling from Grindon I kept the sun to my left, with an eye
on my right, it was only a few Miles later I saw a
Rainbow in a field, it's end seemed to cross through a gate.

It also passed through an open triangle of Blue sky, a very pleasing
Image, and literally chased along the road.

To see the full "Rainbow Gate" image click HERE

A final Quote from Sir Issac Newton ; From his book "OPTICKS"

"In a very dark chamber, at a round hole, about one third part of an Inch board, made in the shut of a Window, I placed a Glass Prism, whereby the beam of the Sun's Light, which came in at that hole, might be refracted upwards toward the opposite Wall of the Chamber, and there form a coloured Image of the Sun"

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How to remember your rainbow order

Richard Of York Gave Battle In Vain