Tips for catching the Northern Lights
If you’re in Arlington and love The Res, you’ve got one of the best local spots for a potential northern lights sighting, especially if you walk down near the water with its clear view to the north. Chasing aurora right here in Arlington is a lot of fun, and half the adventure is learning to read space weather like a pro. To see the lights, you need dark nights, clear skies, a strong solar wind, and a little bit of luck!
The northern lights are the result of geomagnetic forces in the upper atmosphere. The solar wind helps to create the northern lights. There is a score for how strong the solar wind is, called the KP index. The higher the solar wind is, the greater the chances that there will be activity in the skies. The sun goes through 12-year solar cycles, and we are heading right at a solar maximum in 2025/26. When there are more sunspots on the solar surface, the chance of the northern lights is greater.
Tools:
Spaceweather.com (https://www.spaceweather.com) and [NOAA’s Space Weather Prediction Center](https://www.swpc.noaa.gov/) give you official Kp indices and real-time solar wind data: the backbone of aurora chasing.
For local, rapid-fire alerts, sign up for Aurorasaurus (https://aurorasaurus.org) and turn on notifications. There is an app called Aurora for mobile that can also be very helpful. This app can be set up to send push alerts. For Arlington, we need Kp of 6 or above, any lower at our latitude, and it’s usually just wishful thinking.
The trickier stuff lives on the NOAA Real-Time Solar Wind page (https://www.swpc.noaa.gov/products/real-time-solar-wind).
The top graph tells the story:
– Black line: Total magnetic field strength (Bt). Look for peaks above 10 nanoteslas (nT)—these are good signs.
– Red line: The critical Bz, which is the north-south component. You want this red line to dive below zero (with a purple background color), ideally -5 nT or lower and stay there. When it does, that’s the sign that Earth’s field is ready for business.
– Phi GSM (second panel): This shows the direction of the solar wind’s magnetic field. The background color here is key: Red background = “away” from Earth (Phi GSM 45°–225°). During strong storms, you may see sustained red backgrounds. This matched our last local aurora event!
NOAA Real-Time Solar Wind page
Note the pattern seen during the last aurora: Upward spiking black line (Bt), negative red line (Bz) with purple background, and Phi GSM with red background color.
When the Kp index is high (above 6), the black (Bt) line is strong, the red (Bz) line stays south with a purple background color, and the Phi GSM background is red: That’s your cue! Grab a hat, your jacket, your smartphone, and a camera/tripod, and head for The Res. The first thing you might notice, if the show is on, is a faint glow or wispy clouds to the north.
Don’t trust your eyes alone! Your camera (phone in night mode or, ideally, an SLR and tripod with a long exposure) will pull out greens and reds even when your retinas might only see gray.
Best advice: go out with warm clothes, but with even more curiosity and excitement. Leave your expectations behind. Most nights you might just get a quiet walk and a good look at Orion. But when the solar wind lines up, The Res can turn into a front-row seat for Arlington’s rarest light show.
Have fun with it, and if you see the lights when you are out there, be sure to share it with your neighbors!
It’s much more fun enjoying the show with a crowd!
-Bill Lester
Aurora Event May 10, 2024
Aurora Event October 10, 2024
Comet C/2023 A3 (Tsuchinshan-ATLAS) and C/2024 S1 (ATLAS)October 15, 2024
Comet C/2020 F3, or NEOWISE July 29, 2020