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It took one of
the largest solar flares ever recorded for me to capture
this display of the northern lights over Washington's
Central Cascades.
I had been
trying to photograph the aurora borealis for a couple years
- getting up in the middle of the night, driving to a peak
far from city lights and waiting in the cold - but
repeatedly returned home with nothing.
Washington
typically gets a few light shows a year. The catch is
knowing when the light shows will develop - and being lucky
enough to have them develop on a clear night when little of
the moon is showing. I use a couple of web sites to track
the aurora activity and make sure I'm position to capture
the lights any time the conditions appear ideal.
One of the sites
I check most often is from NOAA's Space Environmental
Center. The site, located at
http://www.sec.noaa.gov/pmap/, rates the aurora activity
at both poles on a scale of 1 to 10++. To see the northern
lights from the peaks in Snohomish County, you need a
northern pass reading of 10 or more.
The problem is
that the aurora levels can bounce around a lot. I've seen
the levels jump from 7 to 10 in under an hour and vice
versa. Generally, I head out any time the aurora levels have
consistently reached 9 and 10 over a period of several
hours, even if the level has since dropped to 7 or 8. That's
probably why I had been met with so little success.
That wasn't the
case, though, in late October 2003 when I was lucky enough
to witness the northern lights two nights in a row.
It all started
with word of a near-record solar storm. A mass of particles
thirteen times the size of the earth erupted from the sun
and began racing our way at 5 million miles per hour. At
that speed, it took just 19 hours to travel from the sun to
Earth. The particle storm was rated G5 - the most severe
category. There have been just five solar storms of that
magnitude over the past 15 years, and most of them did not
collide with Earth.
Such storms are
bad for satellite operators and for the electrical grid, but
can potentially result in an aurora borealis display as far
south as Texas. Sure enough, the NOAA site showed aurora
readings of 10 for several consecutive hours. I took a nap
that evening and planned to be halfway up Mount Pilchuck by
midnight when the northern lights display tends to be most
intense. The effort paid off.
The vertical
composition you see above was the image I captured the first
night. To your eyes, the aurora borealis is fairly dim. All
I could make out was the green bands. I could see that the
bands moved around a fair amount, but the color was not
anywhere near as intense as it was in the resulting image. I
couldn't see any of the red at all.
Because of my
long exposure, the camera was capable of recording parts of
the aurora that I couldn't see. I set my digital camera to
simulate ISO 400 film and I used shutter speeds of between
20 and 30 seconds. If I used slower film and longer shutter
speeds, the bands would blur and appear out of focus in the
final image. They really do move around quite a bit. Putting
up with a little grain was a fine trade off for capturing
the bands of light. Even though I couldn't make out all the
colors with my own eyes, the shifting bands were truly
impressive.
The aurora
borealis show didn't last very long. The peak activity
lasted less than five minutes, but I was sure I had a
picture that would work out. And given the severity of the
storm, I decided to try to photograph the northern lights
the following night from a different location. The image to
your right was captured that second night from a road off
the Mountain Loop Highway, east of Mt. Pilchuck. It's tough
to see in the compressed Internet version of the image, but
the big dipper is visible starting at the horizon in the
middle of the image and stretching up and to the right.
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