I do hope that all of you got a chance to see the aurora this past weekend. It was certainly impressive from where I was. This was the strongest geomagnetic storm since 2003. I drove out to Camano Island north of Seattle to get a good look (along with a lot of other people). I got plenty of good photos, and a nice timelapse (below). I am still working on processing them, but I have completed a few. The image above is the last one I took before leaving for the night. If you look closely near the lower center, you will see the constellation of Scorpius. This is significant because Scorpius was in the southern part of the sky. These aurora were so strong that I was able to see them even while facing south.
In case you didn’t get a chance to see the aurora this time around, I thought that I’d use this week’s post to go over some tips and tricks to seeing them.
First caveat: Lower your expectations. I am only being half facetious when I say this. I’ve seen many people come to the observatory I used to work at to see aurora that they know are definitely going to happen and are going to look like everything they’ve imagined, only to be let down by the reality of the situation. So I want to emphasize that you probably won’t see aurora, and that won’t look the way you imagine if you do see them.
Second caveat: Your camera has better eyes than you do. A lot of the time when you see pictures of the aurora, they are the result of long exposure photography. This does not mean that the pictures are “fake” in any way, but because your camera is able to gather more light, it can help emphasize the faint aurora. As a result, you can get pictures of the aurora from significantly further lower latitudes than you can actually see them with the naked eye. So if somebody posts photos of the aurora from, say, Texas, that doesn’t mean they saw the aurora with their eyes. So if you are trying to see some aurora, bringing a camera and a tripod will really help out.
With that out of the way, let’s get on to actually talking about how we can maximize your chances of seeing aurora. And we’re going to begin by talking about how the aurora happen.
The aurora occur as a result of particles from the sun (mostly protons and electrons) running into the Earth’s magnetic field. These particles are largely deflected around the Earth, but some of them are caught by the magnetic field, and follow it until they run into our atmosphere. When they hit gas molecules in the atmosphere, they can ionize them. When the molecules become de-ionized, they will emit light. We perceive this light as the aurora. As the magnetic field lines come back to Earth near the poles, we primarily see the aurora near the north and south poles. Sometimes, large amounts of these particles can be sent our way due to a coronal mass ejection or coronal hole. I’m not going to go into detail about those events here (you can read the Wikipedia pages yourself), but I will quickly note that these events are nothing that we need to worry about.
If the material ejected by the sun is strikes the Earth, large amounts of protons and electrons will run into our magnetic field all at once. This can distort the magnetic field lines, pushing them inwards towards the Earth. We call this a “geomagnetic storm“. Because the Earth’s magnetic field lines are bent out of shape, this will drive the aurora to lower latitudes, making them visible further south (or north, if you are in the southern hemisphere). In addition, the large influx of particles running into the atmosphere will result in better and brighter aurora.
So, if we want good aurora, we need to have a nice geomagnetic storm. Unfortunately, these events are incredibly unpredictable. First, we really have no way of predicting when a coronal mass ejection will occur. And if we do see one happen, odds are it will not be heading towards the Earth. And even if it is Earth-facing, we’re a teeny, tiny target 93 million miles away from the sun, so they often end up missing. To get an idea of what the current aurora forecast is, I recommend consulting the NOAA Aurora Dashboard. Here you can see the current and predicted conditions of the Earth’s magnetic field and the aurora. Of particular note are the kP Index (which ranges from 1 to 9) and the Geomagnetic Storm Index (G, ranges from 0 to 5). In both cases, a higher number means a stronger disturbance of the Earth’s magnetic field (and better chances of aurora).
Third caveat: Forecasts are unreliable. NOAA, NASA, and a few other institutions track the solar wind and make predictions on aurora visibility. However, because of how fickle these events are, the forecasts are usually simply showing the best case scenario. So even if there is a projection for a geomagnetic storm, you can’t really rely on it until the evening of. If there is a prediction that we will have good aurora, I keep an eye on NOAA’s current aurora forecast. This image shows where the aurora are currently likely happening. You can find links to this from websites like spaceweather.com (where you can find lots of other useful information as well).
Now, if we do end up having a geomagnetic storm, there are a few other things we need to consider. First, what time is it? If the geomagnetic storm happens when it is the daytime where you are, you’re out of luck. Second, what is the current moon phase? Even if we have very strong aurora, a bright moon (doesn’t even have to be full) might wipe out your chances of seeing them. Third, what time of year is it? If it is wintertime, the night starts early, and is nice and dark. But if it is summertime, astronomical darkness might not start until very, very late. And finally, what’s the weather like? There’s no point looking for aurora if it is overcast.
Okay, but let’s say that all of these factors have worked out in your favor. What should you do? Well, try to find a place that is very dark, far from city lights and as north as you can get. You also want to have a clear view to the north (or south, if you are in the southern hemisphere). If you have a camera and a tripod, set them up and start taking some long exposures (5-10 seconds is usually enough). The best time to see the aurora will be after astronomical twilight. You can look up when that is for your latitude/longitude online. Aurora tend to peak around midnight, so be ready to stick around late. And finally, once again lower your expectations. If you do see the aurora, it may only be as a faint glow low on the northern horizon. It also most likely be the beautiful green and red you expect, as it needs to be quite bright for you to actually make out the colors. That doesn’t mean it’s not impressive! It just means that it probably won’t look like you expect.
So with all that in mind, here’s my final tip. There is one location you can travel to that has the best views of the aurora, bar none. However, it might be a little difficult to get a ticket to the International Space Station. But for those of us stuck on the ground, at least we can enjoy this incredible 4k footage they’ve recorded.
If you know anyone who would like to receive these, please have them send an email to [email protected]. And if I was too pessimistic about your chances of seeing aurora, let me know and I can take you off the list.
Follow my photography on Flickr and check out my timelapses on YouTube.