Geomagnetic Storm Underway, Aurora Forecast Looks Good Tonight

An aurora-making G2 or even G3 geomagnetic storm is expected tonight. Be sure to watch at nightfall. This aurora is from April of this year. Credit: Bob King

** Update 10:30 p.m. CDT: After a day with lots of auroral activity in the eastern hemisphere, we’ve been in a lull the past few hours now that darkness has come to North America. No aurora to report yet, but it’s only just getting dark here. I’ll update again in a bit.

The aurora smolders near the northern horizon at 1 a.m. Monday morning (July 17). One faint ray is visible at upper left. Credit: Bob King

** Update 1:15 a.m. CDT: We’ve had a low arc and a couple faint rays show in the past hour. Still pretty quiet. Got this sneaking feeling it’s going to erupt 10 minutes after I fall asleep.

Based on the current forecast, the aurora should become visible right at nightfall across the northern sky. If your forecast is for clear weather, and you don’t already have an observing site picked out away from city light pollution with an open view to the north, take some time to find one today. I usually find observing spots by driving around the countryside looking for a quiet gravel road with a view to the north.

Lots of aurora over northern Russia this morning around 10:30 CDT. They’re likely not seeing much because it’s mid-summer, and the sky never gets truly dark at those latitudes. Click here for the current oval. Credit: NASA

No equipment is needed to view the aurora, but many of us like to take a camera and tripod along. If that describes you, you’ll need a camera able to take time exposures up to at least 15 seconds. Because the aurora’s big, a wide angle lens is best. Set the lens to manual focus and your camera to manual (the “M” on the dial). Attach it to a tripod, then use the camera’s “live view” function to focus on a bright star. Don’t have live view? Try focusing on a cloud today and leave the focus there till you need it tonight — don’t touch!

Fireflies send their love last night in a field north of Duluth, Minn. The colored bands are airglow. Credit: Bob King

Auroras vary a lot in brightness. For the faint ones, I open the lens all the way to f/2.8 to let in the maximum amount of light, then dial in ISO 1600 and take 30-second time exposures. With bright ones, keep the lens wide open and the ISO set to 1600 and shorten the exposure time to 10-15 seconds. If your pictures look too grainy at 1600, drop to ISO 800 and expose for 15-30 seconds.

Forecasts can change, so try not to be disappointed if the aurora shuts down early, but at least where I’m sitting on a Sunday morning, the picture for tonight looks rosy. Or should I say green?

10 Responses

  1. Doubt we will see the aurora from southern wyoming but will sure look anyway. Love the final shot of your fireflies and stars, Bob! Gorgeous, Thanks! Lynn

    1. astrobob

      Hi Lynn,
      Glad you liked the fireflies. I was entranced all night with them. It was a new spot for me, and I hadn’t expected so many now as the season starts to wind down.

    2. Bob, I saw no aurora in southern Wyoming (but certainly possible I was not up and looking at the right time) but did witness a blood red sunset with purple, orange and red virga that was completely breathtaking!
      I have a couple of specific questions to ask you about your last two firefly shots this past week. I am not sure this would be the place to ask them, but especially the paired flashing fireflies, several firefly researchers are interested to know more. Could you email me if you get a chance? Thanks. Lynn

      1. astrobob

        Hi Lynn,
        That’s what I always like about aurora forecasts. Even if it doesn’t show, you get outside for a look at the stars, satellites and (inevitably) meteors. I did get to see the aurora that night around 12:30 a.m. but very low in the northern sky. You can e-mail me at rking@duluthnews.com anytime.

    1. astrobob

      Hi Bill,
      Still a bit early. Nothing yet though. And as far as I see at the moment, there’s a lull.

  2. Heidi Harrison

    We have a group planning to go out at 11:00 to take a gander but we are on Park Point so city lights will probably wash them out. Worth a try!

  3. We just so happen to be in Duluth for a family reunion this week so we’re driving around to see if we can check the Aurora off our bucket lists. Any sightings yet tonight?

    1. astrobob

      Hi Shana,

      Nothing yet, but there’s still a chance for a sighting. There’s been a little uptick in activity (in satellite readings) in the last 20 minutes. I’m waiting to see if it translates into aurora.

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