Pathways

[philby]

This is an archive photo about a year and half old. I was photographing eagles when the rainbow appeared. The red brushare blue berry plants, the white in the row is that morning's snow.

[Alan T]

Wow! Natural supersaturation! Good luck & extra quick expert judgement here.

[yesterday]

Awesome shot.

[calr]

Beautiful shot. That rainbow is amazing. What is curious is that there is no secondary rainbow. With a primary that brilliant, I would think that a strong secondary would be present, also.

Cal

[philby]

calr wrote:

Beautiful shot. That rainbow is amazing. What is curious is that there is no secondary rainbow. With a primary that brilliant, I would think that a strong secondary would be present, also.

Cal

I looked at a companion shot, that I kept, made 50 seconds before and 30 feet North of this shot. There is a faint companion rainbow in that frame shot at 35 mm. In this shot, at 40mm, the second rainbow is just out of the frame.

[Alan T]

calr wrote:

...What is curious is that there is no secondary rainbow....

We can't see it in this shot because the raindrops reflecting the sunlight from behind, at a slightly different angle for each colour, after one dispersive refraction into the drop, one bounce off the back of the drop, and one refraction out of the drop back towards us, are so close to us.

In this remarkable shot, we can see where to go and dig for the pot of gold. It's somewhere on the ground in front of the green conifers, and behind the red bushes at bottom right. We are so close to this, that we'd have to crane our necks further than the camera could to see the secondary bow, which arises from one refraction into the drop, TWO bounces round theback of the drop, and one refraction out of the drop back towards us. It's so bright because the 'mirror' at the back of the drops is very close.

All the rays going into the drops are effectively parallel, coming from 93 million miles away. The rays coming out of the drops as (a) the primary, and (b) the secondary bows diverge, at a calculable angle from each other at the source in the drops. The closer we are to the source, the wider apart they seem. Rays between these two angles strike the back of the drop more steeply than the 'critical angle', and go straight on without reflection, which is why the sky appears much darker outside the primary bow than inside.

If we were a mile further back, the apparent location of the raindrops would be painted on the screen of raindrops a mile further away, so the two rainbows would look closer together.

Go get your spades and dig!

[mcliu]

Awasome shot.. Took my breath away..

Liu

[philby]

Thank you Alan T for your great explenation of rainbows.

Here is the other shot showing a faint secondary rainbow.

[Alan T]

Another great shot. Man-made linearity, and natural circularity, beautifully juxtaposed.

[vsch1]

Amazing...right place at the right time. beautiful!