Astronomy Picture of the Day Search Results for "iridescent"

APOD: 2007 November 25 - An Iridescent Cloud Over Colorado
Explanation: Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size. When the Sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too far from the Sun to exhibit striking colors. This iridescent cloud was photographed above Boulder, Colorado last week.

APOD: 2005 September 28 - A Rocket Launch at Sunset
Explanation: What kind of cloud is that? Last week, a sunset rocket launch lit up the sky and was photographed by sky enthusiasts as far as hundreds of miles away. The lingering result was a photogenic rocket plume. Not everyone who saw the resulting plume knew its cause to be a Minotaur rocket launched from Vandenberg Air Force Base in California, USA. The cloud was visible after sunset on 22 September. Fuel particles and water droplets expelled from the rocket swirled in the winds of the upper atmosphere, creating an expanding helix. The noctilucent plume was so high that it still reflected sunlight, where lower clouds in the foreground appeared dark. The above image also captured part of the plume reflecting sunlight as a rainbow or a colorful iridescent cloud. Below the launch plume is the planet Venus.

APOD: 2004 April 13 - An Iridescent Cloud Over France
Explanation: Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size. When the Sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too far from the Sun to exhibit striking colors. Pictured above, an iridescent cloud was photographed near Cannes, France last month.

APOD: 2003 October 14 - Iridescent Clouds Over Aiguille de la Tsa
Explanation: Before the sun rose over the mountains, iridescent colors danced across the sky. The unexpected light show was caused by a batch of iridescent clouds, and captured on film in early September in Arolla, Wallis, Switzerland. The peak in the foreground of the above image is Aiguille de la Tsa. Iridescent clouds contain patches of water droplets of nearly identical size that can therefore diffract sunlight in a nearly uniform manner. Different colors will be deflected by different amounts and so come to the observer from slightly different directions. Iridescent clouds are best seen outside the glare of the direct Sun although they can occasionally be seen to encircle the Sun.

APOD: 2003 March 11 - Iridescent clouds
Explanation: Why would clouds appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size. When the Sun is in the right position and mostly hidden by thick clouds, these thinner clouds significantly diffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts. Therefore, different colors will come to the observer from slightly different directions. Many clouds start with uniform regions that could show iridescence but quickly become too thick, too mixed, or too far from the Sun to exhibit striking colors. Pictured above, iridescent clouds were photographed over Norway two months ago.

APOD: 2000 November 17 - Leonid Sunrise
Explanation: Such beautiful things begin as grains of sand. Locked in an oyster a granule grows into an iridescent pearl, lustrous and lovely to behold. While hurtling through the atmosphere at 70 kilometers per second, a cosmic sand grain becomes an awe-inspiring meteor, its transient beauty displayed for any who care to watch. Framed perfectly between orange clouds at sunrise, this bright meteor trail was photographed from the Joshua Tree National Park in California, USA during the 1998 Leonid Meteor Shower. Appropriately titled "Leonid Sunrise", the picture was recorded on high-speed film (ASA 3200) with a 35mm camera. Its striking colors and grainy, textured appearance suggest a painting on canvas. Of course, you could see Leonid meteors at sunrise for yourself. With clear skies, your next chance is coming up ... tomorrow morning.

APOD: July 14, 1999 - Moon, Planets, and Rocket Trails
Explanation: Are you an early riser? Over the last month or so, the bright planets Jupiter and Saturn have come to adorn eastern skies before sunrise. In fact, astrophotographer Joe Orman anticipated that an early bird's reward for looking east on June 10 would be this pleasing arrangement of Jupiter (top right), a crescent Moon, and Saturn (near center), but he was surprised to also find these eerie, iridescent clouds wafting through the pre-dawn sky over suburban Phoenix, Arizona, USA. The clouds turned out to be rocket engine trails from defense missile tests at the range in White Sands, New Mexico ... about 300 miles away. While the Moon's phase is just past new moon, gone now from the pre-dawn horizon, brilliant Jupiter and Saturn can still be seen high toward the southeast in the constellation Aries.