Iridescence

Circumstance is an opportunity awaiting an outcome. Or, sometimes you are destined to be in the right place at the right time. Today was a circumstance and that outcome was the thrilling sight of an optical phenomenon called Iridescence (also known as Irisation).

This colourful outcome is caused by the diffraction of sunlight on water droplets appearing as bands around the edges of thin clouds such as altocumulus, cirrocumulus, altostratus and occasionally, lenticular clouds. It is associated with the Sun and with the Moon in conjunction with these clouds. You see Iridescence in the transparent surfaces of bubbles and soap-suds, on certain sea shells, on the wings of some magnificent butterflies, even little bugs like stag beetles. It is not to be confused with a Halo, that you sometimes see circling these Orbs. The colours of Iridescence are often described as mother-of-pearl in appearance. Though, I like the description given me by a friend who is an earnest and very harmless Cloudspotter, an affliction that consumes me also: "As if the tears of Angels have fallen onto clouds. The reason being for the tears in the first place are the Angels weeping at the arrival of more souls into heaven and being astounded by their beauty". It may be a tad romantic in the sentiment but honest enough. Though for me such a vista is a wonder of the complex gainian parts that make up our planet.

Surprisingly, Iridescence is fairly common, though not often noticed; wisely due to its often close proximity to the blinding Sun. So, a cautionary tale of commonsense that unbelievably I have seen Cloudspotting contemporaries flout at their peril - never look directly at the Sun, even through sunglasses or (aghast) a camera viewfinder or lens! You are asking for the ruin of your eyes. That aside, on my Cloudspotting adventures I have only seen a handful of this atmospheric treasure and never before snared a half decent photo.

The word Iridescence comes from the Greek, 'iris' meaning rainbow and the English suffix, '-escence' which means, 'derived from or from a state of'. In Greek mythology, Iris (often depicted as a winged maiden), is the personification of the rainbow. In this role she is thought to be a divine messenger between the Sun and Earth travelling with the winds from one horizon to the other and even from heaven to the depths of Davy Jones locker and beyond into the underworld. Certainly one of the more colourful of Greek imaginations and one of the most beautiful as befits her status.

I took this photo from a Park not far my home, where I had intended to spend an hour or so Kite flying (which was going to be my essay and photo for the day). I soon grounded the Kite and watched, again with astonishment, at the display that unfolded. Sadly, within 10 minutes it had fled to another horizon. I then retreated to a nearby Milk Bar to avail of some refreshment instead to settle down after being so thrilled. Whilst waiting for a lime flavoured Thick-shake I was asked, by my old friend, 'Turps' (who owns the local Milk Bar Shop) what did I think is the collective noun for Cloudspotters after he noticed my Cloudspotters badge on my coat-jacket? To my reckoning there is not one, but I offered 'A Chuggery of Cloudspotters' for his indigestion. He just looked askance, wishing perhaps he had not mooted the question in the first place in order to make polite conversation whilst the lime and milk thickened.

Further reading: 'The Weather Identification Handbook', author Storm Dunlop (fair dinkum that's the bloke's name!). Published by The Lyons Press, Connecticut (192 pages): 2003

A useful website where Cloudspotters play is: www.cloudappreciationsociety.org