Ryan Rumpca
Nov, 2021
Preface²
I am by no means an astrophysicist or a hardcore aurora data junkie. I am just a regular, slightly nerdy guy living in an area prone to occasional aurora sightings. Over the last six years, I have been actively keeping an eye on the aurora in the northern Minnesota area. My frequency of reviewing the data has grown exponentially over the last year, and it has become an almost nightly routine. This has allowed me to see the lights dancing almost 10 times in the last year. In this guide I will be distilling the heaps of data down to only a couple of easy-to-remember things to look for.
Preface
The Northern Lights are fickle. Earthly weather forecasts are already difficult as it is, now imagine space weather. This guide will not give you a bulletproof way of seeing the Northern Lights, nor will any other resource for that matter. If I have learned anything from aurora hunting, it is patience. This is only meant to give you the right tools to increase your chances of seeing the elusive Aurora Borealis.
Key Considerations I Look For
Dark Sky Location - Dark skies are extremely important, especially during minor activity. Light pollution from city lights can obscure most of the glow. Do some prior scouting to determine a couple of locations that are suitable. The more north the better, but also find a couple spots close to home. For locations, I use Google Earth to scout locations that are north of any town. I look for northern facing roads, lakes, fields, or any other area I know that has an open view to the north. Use the dark sky map to determine the amount of light pollution in any given area, located HERE.
Moon Phase, Twilight - When people think of light pollution, they normally think of city lights. While this is definitely a huge portion, natural light pollution is often overlooked. Aurora chasers should take into consideration the moon phases and twilight times. The darker the better, so a moon less than 25% full is preferred. If the moon is over 25% full, look for moon rise and moon set times, as that can be a workaround way to still get a dark sky. My favorite resource for researching the moon phases and times is located HERE.
Similar to the moon, the rising or setting sun can also cause light pollution. There are actually three different phases of twilight comprised of astronomical twilight, nautical twilight, and civil twilight. These are ordered from most dark to least dark. Look for times of the night that are not in any of these twilight ranges. My favorite resource for sun and twilight times is located HERE.
High KP index - KP index is a measurement of Earth's geomagnetic activity. Simply put, the higher the number, the further south you have a chance to see them. This is measured on a scale of 1 to 9. In Minnesota, I set alerts for being at least KP4, and will probably go out regardless at KP5 or higher. This will all depend on where you are located, and there is a good general rule of thumb map HERE.
Negative Bz - Bz is the North/South direction of the magnetic field. You want a negative Bz because it is the force that essentially attracts (pulls) particles down from the polar regions. You can think of this as quite literally a giant magnet. The more negative the Bz, the better. Shows usually happen if the Bz is <-5 here in MN, with really good shows happening at -10Bz or less.
Be Patient – The Aurora is elusive. Even if the numbers look great, there is still a very real chance that you won’t be able to see them. Predictions are usually only accurate 30 minutes out, if at all. Solar activity can be forecasted a couple of days in advanced, but there are many factors that need to line up for them to be visible. Be patient if you don’t see them. Worst case scenario you get to spend a quiet, relaxing star-lit night in the woods.
Additional notes - Most pictures you see are not reflective of what you see with your eyes. Our eyes are physically not capable of taking that much light in at one time, so cameras do a lot better. GoPros and even some phones now are doing a better and better job in low light conditions, so you can always give that a shot if you don’t have a camera. If you do happen to see them, they might look like a faint glow on the horizon, possibly like light pollution. Depending on the strength, the real show happens when you start seeing movement. I personally have seen light pillars, waves, sheets, ripples, coronas, and even pulsating. The most common of those listed above are light pillars.
Conclusion
Find dark sky facing north
High KP - >4
Negative Bz < -5
Moon <25% or is not risen
Resources
These are main pages, so play around drilling down into the different reports.
All encompassing, bunch of data in a more scientific display. Government backed so it’s a very solid resource most other pages pull from
All encompassing with a little bit better user interface
Pretty tailored down version of data with decent visuals and a lot of good information
My go-to for on the fly KP and Bz reviewing. Simplified with less clutter. Usually pretty accurate with real time data.
Apps
My Aurora Forecast – Not extremely accurate for KP and free version doesn’t show Bz, but it does allow alerts which is awesome.
Ryan is a freelance photographer and FAA part 107 commercial drone pilot based out of Duluth, Minnesota, United States. Ryan enjoys the extremes of mother nature and is constantly seeking out new experiences that will push the boundaries of his own comfort zone just a little bit more. An avid hiker, camper, and traveler, Ryan enjoys his time experiencing the elements. Catch him up the North Shore or exploring remote places on the other side of the globe.