What do you need? The first thing is the camera. You need a camera that you can use in manual settings. Manual settings are important because the camera software is made for shooting in daylight and the automatic settings the camera will attempt to make the night to day.
The camera should have a timer function or the remote. If you want to use a remote controller, you can purchase the cable version, which does not need batteries. In my experience, wireless triggers tend to clot in the cold. A remote controller or a timer is needed because pressing the button moves the camera and on long exposure it creates motion blur image.
Another important thing is tripod. You will need a tripod because you need long exposure for aurora photos. Without tripod motion blur due to make photos be very unclear.
Basically, that’s what you need from camera, but what kind of camera is best? The Northern Lights often cover a large part of the sky and if you want to get them all to image and perhaps a little more of the landscape, you need a wide angle lens. I use the full frame (FF) sensor cameras with 14 mm and 24 mm lenses, 24 mm which I think is the absolute longest for aurora photos. If you have an APS-C DSLR, for example, the Canon 700D or Nikon D5100, I recommend the 10-18 mm lens. Of course more wide can be found, but they are usually fish-eye lenses, which create a strong distortion and it is not most people's mind. Because of larger pixel size full frame cameras do give less noisy image than APS-C cameras.
What else do you need when you want to photograph the Northern Lights? Because auroras are relatively faint compared to the electric light, you should look for a place where there is minimal light pollution. Location should be selected so that the view of the sky is as open as possible. Torch is quite convenient, but for me there is usually enough light mobile phoneIf you use torch, don’t take your most bright one. It takes time for your eyes to adapt darkness. You will also need warm clothes. If you want to get good pictures of the Northern Lights, be prepared to wait a long time.
Since almost the entire aurora season is a cold you need extra batteries for your camera. Batteries should be kept in pockets under clothes, in order to preserve their power.
Coldness need to be remembered on handling your camera too. If you take your frozen camera to inside, you will get ice not only on it, but also in it. You should keep your camera in your camera bag or plastic bag until it’s warmed up to room temperature. The humidity is the worst enemy of digital camera.
Focusing on. In fact, I usually use auto-focus. I focus on the moon or other bright light at least 20 meter from me. Then I turn the manual focus and I no longer touch focus. Another good option is to use the camera's rear screen magnification and focus manually.