16 March 2016 / leggypeggy

The Northern Lights perform

aurora borealis, Coldfoot, colour, night sky, RoadScholar, science, trees, Wiseman

Swirling aurora borealis with trees

We drove north to Coldfoot—into the Arctic Circle—and then farther on to a village called Wiseman.

A small mining community, Wiseman was founded by gold miners who abandoned Slate Creek (later renamed Coldfoot) in 1919 to try their luck there.

Today it is one of the best light-free places in Alaska to view the Northern Lights, or aurora borealis. It’s three miles from the Dalton Highway and with only 13 residents, it’s easy enough to tell everyone to turn off their lights at night.

Aurora borealis in Wiseman

We headed up to Wiseman on Thursday at 10:30pm. We were supposed to go on Wednesday but it was so cloudy we negotiated to wait it out until Thursday and hope for better weather. We were blessed with perfect conditions.

So all we had to do was wait for the aurora to turn on the show.

Actually we could see the aurora gearing up while we were still in Coldfoot, so we were confident of seeing at least some activity.

I’m not going to go into all the science of the aurora. Even today there isn’t a full understanding of how it’s formed, but it has to do with the interaction between solar winds and the earth’s magnetosphere.

Aurora with pinks 2 Aurora with pinks 1

This is what a sign in the Fairbanks cultural centre said. ‘The aurora receives its power from the sun. When sunspots flare on the sun’s surface, charged particles radiate out across the galaxy on the solar wind. About three days later some of these charged particles—protons and electrons—reach earth. The earth’s magnetic field pushed these particles toward the poles. Like a neon sign, these ‘charged particles “light up” gases in the upper atmosphere 60 to 500 miles above the earth, producing a colourful array of light swirling and rippling throughout the sky.’

We saw a 40-minute film at the cultural centre that said severe aurora displays can and do interfere with public utilities. Apparently a whole electrical network in Canada was knocked out in 1989.

Aurora with pinks and trees

But in Wiseman we didn’t worry much about the science. We were there for the show—and a show we got.

It took me several goes to figure out the best camera settings and I still don’t know if I found the very best ones. I was using a Canon 600D with an EFS 15–85mm lens.

My settings were an f-stop of 3.5 (couldn’t get as low as 2.8), a shutter speed of 15 seconds (10 wasn’t enough) and an ISO of 800. I set the camera to manual focus and put that on infinity. Here are the results.

Aurora fading a bit

The show started to die down and we were going to head home about 1:30am. We voted to wait a while to see if another display materialised. Wow, we were glad we waited. Most of the pics here are from a display performing, off and on, for about 10 minutes just after 1:35am.

About the colour
The most common auroral colour is yellow-green. It is produced by oxygen atoms about 60 miles above the earth. High altitude oxygen atoms (about 200 miles up) glow a rare red, while nitrogen molecules emit a purple tinged with red. But keep in mind that the camera sees these better than the naked eye. That said, I could see the colour in these.

P.S. I decided that these didn’t need captions.

Aurora borealis in Alaska