Of all the phenomena you can view in the night sky, the northern lights may be the most spectacular. The lights are created by charged particles from the sun, interacting with gaseous particles in our atmosphere. These lights also appear in the southern hemisphere, where they are known as the southern lights. Another name for the northern version is aurora borealis (southern is aurora australis).
How to find northern lights
You can view a forecast for the northern lights online here. This website gives you a general idea of where the northern lights will be visible on any given night. For example, if you are in the northern continental United States, you might be able to see the northern lights if the forecast is 5 or higher. However, to get the best chance of viewing the northern lights, you’ll need to travel even farther north. To discover the best locations, try to find a day when the forecast on the above website is a 1 or 2. Anywhere within the bright green circle is a prime viewing spot for the northern lights. Some places that are somewhat easier to access in prime viewing areas are Wiseman, Alaska; Yellowknife, Canada; Iceland and northern Norway.
What lens to use
When shooting the northern lights, it is very helpful to use a fast lens that has an aperture of f/2.8 or wider. These lenses can let more light into the camera, which will yield higher quality images at night. A good option is the Rokinon 14mm f/2.8, which costs round $300. This is an ultra-wide angle lens, which is important when photographing something as expansive as the northern lights. Another option is the Nikkor 14-24mm f/2.8. This is a phenomenal lens, but it does cost almost $2,000.
Camera settings and exposure
You’ll typically need to use the widest aperture on the lens, and for shutter speed, you’ll normally want to use exposures between 10-15 seconds. If the lights are moving rapidly in the sky, they can start to blur too much with longer exposures. If the northern lights aren’t moving rapidly, you can get away with exposures of 20-30 seconds. You should use the highest native ISO on your camera that doesn’t cause the highlights to be overexposed (a native ISO is one that is represented by a number, as opposed to letters, like H1 or H2). Be careful, though because when the northern lights become really bright, it is possible to overexpose the shot.
I recommend underexposing the images a little, so that you won’t risk blowing out the highlights, if the lights suddenly brighten. You’ll want to frequently check your histogram to make sure you’re not coming close to clipping the highlights. If you are, you’ll need to lower the ISO or exposure length.
The northern lights can fill up most of the sky, and even ultra-wide angle lenses may only capture a portion of the display. To overcome this problem, you can create stitched images to capture more of the scene. A stitched image is one where you take multiple shots, each comprising a small part of the scene you want to photograph. You then later use computer software, like Lightroom or Image Composite Editor (Windows only), to stitch these images together, to produce an image of the whole scene. The great thing about stitched images is that they will also produce larger images with more detail, and less noise.
If the aurora is bright and moving fast, you’ll typically want to use a very wide lens, like 14mm, to create a single-row stitched panorama. You’ll have to take all of the images pretty quickly, otherwise, the aurora can move so much that the images won’t stitch together seamlessly. If the aurora is relatively dim, it doesn’t tend to move as fast. In this situation, it’s possible to do multi-row stitched panoramas with up to 20 images. These large stitched images can help minimize noise, which is more noticeable when the aurora is fainter. I recommend a 24mm lens to capture such images.
When to look for the lights
The best time of the year to photograph the northern lights is near the spring and autumn equinoxes, in March and September. The northern lights tend to be somewhat more active during those months than others. Never plan a trip to photograph the northern lights between late-April and early-August. During this time, it isn’t dark for very long, if at all, at the far northern latitudes. If you plan a trip in December or January, it will be dark much of the day, if not all of the day. However, it can be bitterly cold during this time, so spring and autumn is still preferable for all but the most adventurous photographers.
Since it can be so cold when shooting the northern lights, it’s possible that your lens will fog up over the course of the night. Lenses fog up much faster when they are taken from a warm location to a cold one. One way to prevent this is to keep your camera equipment cold, by storing it in the trunk of your vehicle rather than in a warm room. You will, however, want to store your batteries in a warm location, as cold batteries do not last as long as warm ones, so this can help maximize battery life. Another option to prevent a lens from fogging up is to attach hand warmers to the side of it using rubber bands to help keep it warm.
You can shoot the northern lights under almost any moon phase. The aurora will be brighter under no moon, but any foreground in your shot will likely be rendered as a dark silhouette. Under a full moon, the foreground will be well-illuminated and the aurora will be fainter, but this may not matter. The northern lights are often so bright that they will be easily visible under a full moon. My favorite time to shoot the northern lights is under a moon that is 20%-50% illuminated. It will be dark enough to see the stars and aurora a little better than under a full moon, and you’ll still be able to render a lot of detail in the foreground. In order to be able to shoot under a variety of conditions, I recommend planning a trip so that you arrive near a new moon, and leave near a full moon.
Practice near home first
One mistake I’ve seen photographers make is to go on an expensive trip to see the northern lights without having done any night photography beforehand. They come away with subpar images that are out of focus, or improperly exposed. Unless you live in an area where you can see the northern lights, I recommend becoming proficient in night photography before paying for an expensive trip to see the aurora. Photographing the northern lights is more difficult than photographing most other night scenes. The lights can move fast and may not appear for very long, so you need to be able to make the most of your time when the lights are out. If you practice with easier subjects beforehand, you should be able to come away some great images!