How? Well, that’s not easy to tell but I’ll try to inform you as easy as possible.
There are different possibilities which depend on which gear you have and what type of conditions you have (snow in front or not).
With a cellphone: Quite impossible, you will get it on photo, but dark and with a lot of noise.
A DSLR camera or full frame: Now we’re talking. Doesn’t matter what type, as long as you have a steady tripod and you can set your shutter time, aperture and ISO it is fine.
I took pictures with a Canon 70D, a camera with a crop sensor and a wide angle lens from Samyang, 10mm f2.8 (so basically it is 16,8mm). If you have a full frame, I would recommend a 14mm lens. You can shoot with f4 but 2.8 is recommended.
Focussing: Set your focus on MF (manual focus) and turn it on infinity (∞-symbol). But this is the tricky part, infinity is not always sharp, you have to turn is slightly to the left or the right (try it during the day while focusing on an object far away and look when you have your focusing ring on the right spot).
Try to shoot in M (manual) and set the f on 2.8 (4 or lower if you don’t reach 2.8) and set the shutter time on 6 seconds with an ISO of +-640. If you have strong lights and a snowy field in front of you, it might be too bright so try a faster shutter speed (f.e. 4s).
If you have a dark field in front of you and a less bright aurora or you shoot only in the sky, your photo might be too dark so you will have to pump up ISO or shutter speed.
Then, it also depends on the speed of the light. If it dances fast, a shutter time of 6 seconds is too fast. So pump up the ISO and try a shutter speed of 2-4 seconds. If the light moves slowly you can even go to 10 seconds and reduce the ISO so you have lesser noise.
If you’re shooting with a full frame, try ISO 2800 or 3200 and a shutter speed of 1,5 or 2 seconds, you won’t get too much noise with this.
So it basically is trial and error. Be sure to set up your gear, because before you know it, it might be there (and gone again)
Three more important hints to avoid unsharpness:
- Turn of your vibrate reduction (if it’s on a tripod it doesn’t need to reduce it, it will work on the opposite way, it will reduce something there is not.
- Turn of the noise reduction in your camera, it will take too long after every photo to process this and you will lose valuable time.
- Use a 2 seconds delay time, also for avoiding unsharpness.
(If you have more questions: feel free to ask!)