Colorful Lunar Eclipse   
       
   Sept. 18, 2014:  On Wednesday morning, Oct. 8th, not long before sunrise, the   
   bright full Moon over North America will turn a lovely shade of celestial   
   red.  It's a lunar eclipse-visible from all parts of the USA.   
       
   "It promises to be a stunning sight, even from the most light polluted   
   cities," says NASA's longtime eclipse expert Fred Espenak. "I encourage   
   everyone, especially families with curious children, to go out and enjoy the   
   event."   
       
    http://www.youtube.com/watch?v=wmCK2Pfsh0Y&feature=youtu.be   
       
   A new ScienceCast video examines the red and turquoise colors sky watchers can   
   expect to see during the Oct. 8, 2014, total lunar eclipse. Play it   
       
   From the east coast of North America, totality begins at 6:25 am EDT.  The   
   Moon will be hanging low over the western horizon, probably swollen by the   
   famous Moon illusion into a seemingly-giant red orb, briefly visible before   
   daybreak. West-coast observers are even better positioned. The Moon will be   
   high in the sky as totality slowly plays out between 3:25 am and 4:24 am PDT.     
   During a lunar eclipse, the Moon passes deep inside the shadow of our planet,   
   a location that bathes the the face of the Moon in a coppery light.   
       
   A quick trip to the Moon explains the color: Imagine yourself standing on a   
   dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down,   
   completely hiding the sun behind it. The eclipse is underway.   
       
   You might expect Earth seen in this way to be utterly dark, but it's not. The   
   rim of the planet is on fire! As you scan your eye around Earth's   
   circumference, you're seeing every sunrise and every sunset in the world, all   
   of them, all at once. This incredible light beams into the heart of Earth's   
   shadow, filling it with a coppery glow and transforming the Moon into a great   
   red orb.   
       
   However, red is not the only color.  Many observers of lunar eclipses also   
   report seeing a band of turquoise.   
       
   http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2014-Fig03.pdf   
       
   Click to see a worldwide eclipse visibility map   
       
   The source of the turquoise is ozone. Atmospheric scientist Richard Keen of   
   the University of Colorado explains: "During a lunar eclipse, most of the   
   light illuminating the moon passes through the stratosphere where it is   
   reddened by scattering. However, light passing through the upper stratosphere   
   penetrates the ozone layer, which absorbs red light and actually makes the   
   passing light ray bluer." This can be seen, he says, as a soft blue fringe   
   around the red core of Earth's shadow.   
       
   To catch the turquoise on Oct. 8th, he advises, "look during the first and   
   last minutes of totality. The turquoise rim is best seen in binoculars or a   
   small telescope."   
       
   The depth and hue of lunar eclipse colors depends a lot on the dustiness of   
   the stratosphere.  When volcanoes erupt and chock the stratosphere with   
   aerosols, lunar eclipses can turn such a deep red that the Moon looks almost   
   black.  That's not the case this time, however:   
       
   "Despite some recent eruptions that look spectacular from the ground, there   
   have been no large injections of volcanic gases into the stratosphere," says   
   Keen. "In the absence of volcanic effects, I expect a rather normal   
   reddish-orange lunar eclipse similar in appearance to last April's eclipse."   
       
   In other words, this is going to be good.   
       
   Espenak notes that "the total lunar eclipse of Oct. 8 is the second of four   
   consecutive total lunar eclipses. Such a set of total eclipses is known as a   
   tetrad." The next eclipse in the tetrad is six months from now, in April 2015.   
       
   "Don't wait," he urges. Mark your calendar for October 8th, wake up early, and   
   enjoy the show.   
       
   Credits:   
   Author: Dr. Tony Phillips |  Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
   More information:   
       
   NASA's Eclipse home page   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)