AURORA WATCH: Sky
watchers from Alaska to Scandinavia should be alert for auroras
tonight. A solar wind stream is buffeting Earth's magnetic field
and causing arctic geomagnetic storms: gallery.
ANTARCTIC CLOUDS:
It's that
time of year again; the ozone hole is opening over the South
Pole. People in Antarctica need no special instruments to know this
is happening. They can tell just by looking at the sky:
"These are Type II Polar Stratospheric Clouds (PSCs)
over Australia's Mawson station in Antarctica," says Andrew
Klekociuk of Australia's Antarctic Division. "This type of
cloud is intimately associated with the formation of the ozone hole,
which is currently reaching peak
size."
PSCs form when temperatures in the stratosphere become extremely
cold, below -78° C. ("Balloon-measured temperatures in the
vicinity of the clouds were -86 degrees C," notes Klekociuk.)
They spell trouble for ozone; tiny ice crystals and droplets within
the clouds provide surfaces where CFCs are converted into ozone-destroying
molecules. Those same crystals diffract sunlight, producing vivid
nacreous colors.
Peter Tsimnadis of Mawson Station took the picture using a Nikon
D80 on Aug. 28th. Other similar displays have been seen since.
Klekociuk says, "see our web site for more
information."
HARVEST MOON 360:
The sky is a big, beautiful place. Unfortunately,
human eyes can only see about
180o
of it at once. Click on the sunset to experience the full 360o:
"I created the panorama by stitching together
12 frames shot at 30° intervals using my Canon
20Da camera," explains photographer Alan Dyer of Bassano,
Alberta. "It was the night of the Harvest Moon, Sept. 14th.
Note the Moon rising in the east embedded in the arc of Earth's
shadow and the bright western sky opposite the Moon on the left.
The clouds added wonderful color."
All in all, "it nicely captures the 'big sky'
scene of a prairie sunset and moonrise," he says.
more images: from
Tom Soetaert of Lawrence, Kansas; from
Mohamad Soltanolkottabi of Esfahan, Iran; from
Michel Hersen of Portland, Oregon; from
Erik Thibado of Eau Claire, Wisconsin;
Sept.
2008 Aurora Gallery
[Aurora Alerts] [Night
Sky Cameras]
|