Driftless Dark Skies: Northern Lights

December 7th, 2017 by John Heasley

By 7:30pm on November 7, I was already a pretty happy stargazer. I had been out for an hour and a half with a good astrobuddy touring the clusters, galaxies, and nebulas of the autumn sky at a dark site near Governor Dodge State Park. Our hands and feet were getting cold, and we were pondering what final stellar sights to see before calling it a night and putting the telescope away. Then I saw an unexpected glow low in the northern sky and luminous spikes flaring up through the Big Dipper. The northern lights had returned! I hadn’t seen an aurora since St. Patrick’s Day 2015. I quickly called an astronomy friend who spread the word by phone, email, and Facebook and put my phone away. For the next half hour, I was awed by the pulsating pillars and the ebbing and flowing of the ethereal lights. The finale was the rising of the Waning Gibbous Moon around 8:15 washing out the aurora.

Northern lights are rare and challenging to predict, but here’s how you can see them. You need five things to line up. Solar activity. We see auroras when charged particles from our Sun light up Earth’s upper atmosphere. The University of Alaska Geophysical Institute has a clear map showing where auroras may be visible. NOAA NWS Space Weather Prediction Center can let you know how active the solar wind has been and how likely northern lights are for the next day or two. Spaceweather.com has great information on solar activity and you can subscribe to alerts. Great Lakes Aurora Hunters send out Facebook alerts. We are now in a period of less solar activity. Night. We often miss great auroral displays because they arrive during the day when our part of the planet is facing the Sun. Nothing to be done except be happy for our friends in Scandinavia where it’s already dark. There are not more northern lights in the winter, but we are more likely to see them because nights are longer. In June, there’s only four hours of darkness between dusk and dawn. In December that triples to twelve hours. Dark Skies. We have those in abundance in the Driftless Area. It helps even more to get away from village lights. Have a spot in mind that is nearby with clear and dark views to the north. Our many ridgetops are great.  So are areas with Amish communities.  No Moon. Only the brightest auroras are visible with moonlight, so times around the Last Quarter or New Moon are best. Clear Skies. We’ve missed some great displays because it was overcast. Just enjoy the photos folks are posting from less cloudy areas. When everything aligns, it’s awesome and all the more awesome because auroras are so ephemeral.

It helps to dark adapt. The longer we are in darkness, the more sensitive our eyes become. Avoid car lights and flashlights and cell phones. The last one is tough because smartphone cameras are excellent at recording more color and detail than our eyes experience. Maybe take photos when you first go out or after you’ve gazed for a while. Join your fellow stargazers in Iowa County Astronomers or Starsplitters of Wyalusing or follow Driftless Stargazing on Facebook. We tend to be outside looking up when auroras arrive and love to share the joy.

John Heasley is an astronomy educator and stargazer who enjoys connecting people with the cosmos. He volunteers with NASA/JPL as a Solar System Ambassador. For more information about stargazing in southwest WI, like Driftless Stargazing LLC on Facebook and find out whenever there’s something awesome happening in the skies. Driftless Dark Skies appears monthly in the Voice of the River Valley.

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