SUNSET RAINBOW: The sun was setting on Oct
Near sunset and just after a rain shower on Oct. 7, Victor Bobbett of Phoenix,
Arizona captured this complete rainbow with a Sony Cybershot DSC-75 digital
camera.
The rainbows -- a second one is fading away in the upper left -- are taller
than many you might have seen. On NASA's Spaceweather.com site, where the photo
first appeared, atmospheric optics expert Les Cowley explained the height.
"High in the sky rainbows like these occur close to sunset or sunrise when
the Sun is low," Cowley said. "Rainbows are always centered on the anti-solar
point exactly opposite the Sun and this point gets higher as the Sun sinks."
The web cam tipoff
photo. |
Because the scene was so wide, the photograph is
actually two images spliced together. That it was captured at all owes to the
Internet.
"I have a web cam set up
that I use to sometimes take sunrise and sunset photos to email to friends and
family, and I just happened to see that the rainbow was in the shot," Bobbett
said in an e-mail interview. "I was amazed at the colors of this rainbow at
sunset, so I ran outside to try and capture its beauty. Normally, I would like
to find better scenery for such a shot; without buildings and power lines, but
with rainbows, and the Sun setting, time was not a luxury!
Cowley explains the colors: "The bow colors are those
of sunsets, reds and orange with almost no blue. Blue light is preferentially
scattered out of sunset rays during their long low passage through the Earth's
atmosphere."
Readers interested in other ways light interacts
with the atmosphere can check out our Sky
Scenes photo gallery.
-- Robert Roy Britt
Credit: Victor Bobbett
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