^ PHOTOMETEORS, by JesГєs MartГnez-FrГas Archived at the Wayback Machine.

'Cirrus cloud iridescence: a rare case study'.

^ Gedzelman, Stanley David (1 June 1988).

When the particles in a thin cloud are very similar in size over a large extent, the iridescence takes on the structured form of a corona, a bright circular disk around the Sun or Moon surrounded by one or more colored rings. Iridescence is therefore mostly seen at cloud edges or in semi- transparent clouds, while newly forming clouds produce the brightest and most colorful iridescence. The cloud must be optically thin, so that most rays encounter only a single droplet. If parts of clouds contain small water droplets or ice crystals of similar size, their cumulative effect is seen as colors. It can extend up to 40 degrees from the Sun. Irisation is caused by very uniform water droplets diffracting light (within 10 degrees from the Sun) and by first order interference effects (beyond about 10 degrees from the Sun). Larger ice crystals do not produce iridescence, but can cause halos, a different phenomenon. Iridescent clouds are a diffraction phenomenon caused by small water droplets or small ice crystals individually scattering light. Irisations are named after the Greek goddess Iris, goddess of rainbows and messenger of Zeus and Hera to the mortals below. Other aids are dark glasses, or observing the sky reflected in a convex mirror or in a pool of water. This may be overcome by shielding the sunlight with one's hand or hiding it behind a tree or building. When appearing near the Sun, the effect can be difficult to spot as it is drowned in the Sun's glare. The colors are usually pastel, but can be very vivid or mingled together, sometimes similar to mother-of-pearl. Iridescence is also seen in the much rarer polar stratospheric clouds, also called nacreous clouds. They sometimes appear as bands parallel to the edge of the clouds. This fairly common phenomenon is most often observed in altocumulus, cirrocumulus, lenticular, and cirrus clouds. The colors resemble those seen in soap bubbles and oil on a water surface. вЂњAmazonвЂ™s kind of eating their lunch.Cloud iridescence over County Kildare, IrelandД¬loud iridescence or irisation is a colorful optical phenomenon that occurs in a cloud and appears in the general proximity of the Sun or Moon. вЂњThere are almost 2,000 bookstores in the country, and only about 150 of them have good online shopping platforms,вЂќ he says. Bookshop uses book wholesaler Ingram to fulfil orders.Д¬EO Andy Hunter says the crisis is forcing many bookstores to do what they hadnвЂ™t done beforeвЂ“adapt to the online reality. вЂњIndependent bookstores, and booksellers, get a lifeline just when they need it most,вЂќ writes Alex Lauer in InsideHook of the appearance on the scene of .ДЄny American Booksellers Association store can sign up to the website and sell books, netting 30% of the sales directвЂ“she reportsвЂ“as opposed to 40-45% if they set up a sales platform themselves. book retailers who donвЂ™t have an online presence. ThereвЂ™s another solution out there for the many U.S. readers delight to their doorstep by kicksled Kiruna Bokhandel Amazon Alternatives For Indies

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Corona weather clouds