Infrared rainbows

It was Robert Greenler who, having deduced that there should be an infrared component to a terrestrial rainbow, finally succeeded in photographing a natural one in 1970. I've had a go myself and if the sky does what you need and the camera is steady enough it is not too difficult to give it a go yourself.

Scientific American recently published an article entitles Think You Know Rainbows? Look Again, which discussed and showed examples of rainbows that were not particularly rainbow coloured, including a white one and a red one.

The red example in the article (reproduced above) was taken from the Wikimedia Commons, and was taken by Jason Campbell in 2011. The cause, as the article explains, is that the light source is a setting sun and at this point only red light was available to be refracted by water droplets to form the bow.

You probably see where I'm going here. Let's assume that near-IR is also in the sunlight as the sun sets and that this remains a little after the red has gone. In this case it should be possible for an infrared-only rainbow to exist.

Presumably anyone with a suitable light source and some fine mist could produce one in the lab but has anyone managed to take a photograph of such a thing 'in the wild'?

[As an aside, I recently saw that the light from a rainbow is polarised along the circumference of the bow. Obvious when you think about it but I'd never noticed before.]

October odds and ends

A couple of items for your interest.

Shutterbug published a lovely appreciation of Sir Simon Marsden on October 5th. I also found him very communicative and helpful at the time of the Centenary and really regret not meeting up, especially now I live a lot closer than I did in 2010. This has prompted me so that this year I've decided to desert Ansel Adams and get my 2016 calendar from the Marsden online shop.

Rather oddly, considering the piece dates back to August 2014, New Scientist just tweeted a link to an edition of their 'Last Word' column, which asks 'How far beyond the visible spectrum does a rainbow extend?'. The responses discuss both UV and IR extensions of what we see, and especially how those might be more dominant on other worlds such as Titan. It reminds me of the work of Robert Greenler who, having deduced that there should be an infrared component to a terrestrial rainbow, finally succeeded in photographic a natural one in 1970.

I recently had a visit from Ed Thompson and had a sneak preview of his upcoming book of colour infrared photographs. I'll write more about this when it's published but suffice to say there's lots of red and a delightful conceit in the way the book is packaged. In the meantime if you're in the vicinity of the Rough Print Gallery (14 Bradbury Street, Dalston in London) then images from the Red Forest and The Village portions of his epic Unseen project will be on show. The gallery Tumblr stream tells us that it's part of the White Rabbit Restaurant and the gallery is open 10-5 Wednesday/Thursday and during the restaurant opening hours. Starts 15th October and runs to the 21st.

I think that'll do for the moment.