Driftless Dark Skies: Northern Lights

​It was such a thrill to see the amazing auroral display on March 23 and then again on April 23. I remember so many nights standing in the dark waiting for northern lights that never appeared. But those two nights, I watched in wonder for hours as the storms intensified and pulsed and arched high overhead and the ethereal lights ebbed and flowed. I had not see such activity since St. Patrick’s Day 2015 and would have called either night a once-in-a-decade event. The total solar eclipse of August 2017 is still the most awesome skywatching experience of my life, but these two are at the top of my list. I loved hearing (and seeing the pictures) from so many in the Driftless Area and beyond who were also wowed. And sad to hear from others who missed it. Here are some tips so you can be part of the next appearance.

WHY WE SEE THEM. We see auroras when charged particles from our Sun light up Earth’s upper atmosphere. There are satellites watching for eruptions from the Sun and monitoring the solar wind. We are at a time in the eleven-year solar cycle when activity is predicted to increase with “solar max” happening in 2025.

WHEN TO SEE THEM. Northern lights are rare and challenging to predict. No one can give you an exact time when they will happen–only a probability and a range. We can miss out on some great displays that happen during the day or when it’s cloudy or when moonlight interferes. So much has to align. I watch for Geomagnetic Storm Watches from NOAA NWS Space Weather Prediction Center. These are very much like Winter Storm Watches and Warnings. They also have a 3-day forecast. NOAA classifies storms G1-5 and disturbances in Earth’s magnetic field Kp0-9. It’s also a good sign when Bz goes negative. At latitudes as far south as the Driftless Area of WI/MN/IA/IL, you might see a low faint glow at G1/Kp5 (minor storm). If skies are clear, I will head out to a dark sky site to have a look at G2/Kp6 (moderate storm) and especially for G3/Kp7 (strong storm). The awesome (and rare) displays this spring were G4/Kp8 (severe). G5/Kp9 (extreme storm) has not happened since 1859. It’s best for GPS and our power grid if it doesn’t. If all the numbers are too much to follow, University of Alaska has excellent visuals to make it all clearer. Keep in mind that NOAA and UofA tell time with UTC which is 5 hours ahead of CDT and 6 hours ahead of CST. To see a forecast for this evening, check for the next day. I like getting alerts from the Space Weather Live app. Driftless Stargazing will post by afternoon if it looks like there’s a good chance to see aurora and post again when I actually see them. Then I put my phone away and enjoy the show. I do my best to let people know, but I am really much better as a person than an aurora app?

HOW TO SEE THEM. The readiness is all. Have a convenient and familiar dark sky site in mind. We have those in abundance in the Driftless Area and a light pollution map will help you to identify good places. It helps to get away from town lights and to keep them to your south so that you have a clear and dark view to the north. The views are better from the ridgetop rather than down in the valley. Public lands such as the future Kickapoo Valley Dark Sky Park in Vernon County and Lower Wisconsin Riverway are excellent locations. It helps to give yourself 20-30 minutes to fully dark adapt. The longer we are in darkness, the more sensitive our eyes become. If you need a little light, red or amber is best. 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 can see. Maybe take photos when you first go out or after you’ve gazed for a while. And adjust your expectations. The photos you see the next day are long exposure and much more colorful than what you saw live. Make sure you are warm and comfortable. I often wear my winter jacket and insulated boots and cap and gloves. Bring a blanket and chair and warm beverage and snacks.

HOW TO CONSERVE THEM. So many people cannot be awed by the northern lights and other wonders of the night sky because of the spread of artificial light at night. Good lighting keeps us safe by shining on the ground and not in our eyes or into the sky. Learn more from the International Dark-Sky Association how smart lighting is better for the ecosystem, healthier for humans, and less wasteful of energy and money. Start at home by only using the light you need when you need it and making sure that it is shielded. Talk to your neighbors about lights that may be trespassing on your home or preventing you from enjoying the night sky. Let your local government and community schools and businesses know you care about smart lighting and starry skies.

Northern lights are all the more awesome because they are so unpredictable and ephemeral. Humans have a heritage of being awed by them going back thousands of years. That heritage is worth preserving for future generations. Be a good ancestor!

Graphic is from the University of Alaska-Fairbanks Geophysical Institute showing the extent of a G4 Severe Geomagnetic Storm.

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 , with the International Dark-Sky Association as an Advocate, and the International Astronomical Union as a Dark Sky 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.