The northern lights were spectacular last night across northern Minnesota! Just by chance, a fellow photographer and I were teaching a class on night sky photography, and our group of 13 headed down to the rocky shore of Lake Superior outside the city of Duluth to practice taking pictures of the moon and stars. The partly cloudy sky made for some cool time exposures of stars and moving clouds.
While we knew that the NOAA space weather service had forecast aurora based on observations of recent flares in several large sunspot groups, you can never be absolutely certain that one will materialize. Exactly how Earth’s magnetic field interacts with charged particles from the sun can change unexpectedly and defy predictions. This time however, the forecasters were dead-on.
Then about 10:30 p.m., when the eastern sky should have been dark, I noticed an odd glow as if the moon were about to rise. Wait a minute. Since the moon was at first quarter phase and setting in the west, this had to be something else. We checked the its color by taking a few quick time exposures with our cameras. Yes! Every display window glowed with the telltale green of excited oxygen molecules, a clear indication that the aurora was afoot. While dim auroras appear colorless to the eye, a sensitive camera chip easily records color in a time exposure photo.
Clouds came and went as the soft, diffuse glow swelled over the next hour to fill most of the northern sky. In time, the glow intensified, occasionally erupting into short arcs pierced with shimmering rays. Between quiet conversion, we clicked away, our camera LCD screens flicking on and off like fireflies as each person adjusted exposure and composition.
Around 12:30, after swinging to and fro between ‘quiet’ glows and sudden bright arcs, a vast, tornadic display of rays gathered in the east and surged straight to the zenith. It took our collective breath away and may have even caught the attention of the teens sitting nearby quietly texting one another all night.
Lake Superior reflected the pulsing lights above as Jupiter rose in the east. Our group was as rooted to that pebbly beach as the legs of our tripods – no one dared leaves less they miss another outburst.
The aurora never quit. More surges and arcs appeared low in the north, while rays twirled around nearly overhead in a faint coronal display. By 1:45 things quieted down enough that we could start to hear those little voices inside telling us to either get some sleep or maybe drive to a Perkins for a bite to eat. All that enjoyment took a surprising amount of energy.
I got home around 2 and watched the waning glow until my little voice said it was time for bed. While the big storm is now subsiding, there’s a chance for some additional aurora tonight. Be sure to take a look up just in case.