Northern lights

What is a polar aurora?

They are called aurora borealis or northern lights in the northern hemisphere and southern aurora in the southern hemisphere, but they result from the same phenomenon. The solar particles electromagnetize and the release of this energy creates this colored phenomenon. If auroras are generally green, it's simply because it's the color released by oxygen, the dominant element in solar particles. However, depending on the altitude and the components of the particles, purple, blue or red polar auroras can also be observed.

The power of dawn depends on strictly physical phenomena that can be measured. Which means that we are also able to provide a minimum!

Where to observe polar aurora?

To admire the aurora, we must get closer to the poles. In general, you must enter the Arctic Circle or Antarctic, to have a good chance to see!

When can we observe them?

To see a polar aurora, it must be dark, so the best time is between September and April.

We must avoid full moon weeks (applies to all night shots in general) because it generates a lot of stray light.

To know if it will be possible to see an aurora polar, there are two data to take into account: the weather and the index Kp.

They occur at high altitude, well above the clouds: it requires a clear sky to have the chance to observe them. The index Kp indicates the aurora probabilities. It's not 100% reliable, but it's a good index.

There are some sites and applications giving forecasts.

Equipment

It takes a tripod and a camera, it is possible with any camera that has a manual mode and with which one can adjust the ISO manually, even if the best results will be obtained with a SLR.

Choose a wide-angle light, to take a picture of a little landscape too.

Also provide a headlamp and what to warm, because near the poles, at night, the temperatures are very negative.

Remote control or self-timer

If you have a Remote Trigger Remote, then take it out, it's the right time.

If you do not have one, simply set your device to self-timer. For example, at 5 or 10 seconds. In this way, your device will have a few seconds to stabilise between the moment when you press the button (which causes a small earthquake in the case) and the triggering of the shooting.

The technique of shooting

Shift your focus into manual focus (turn off autofocus) and set the aperture to the smallest number that your lens will allow you to achieve (ideally, you should have an aperture smaller than or equal to f/2.8) .

Choose an ISO value between 800 and 3200 (1600 is a good value to start). The more you increase it, the more you will have what is called "noise", that is to say that your photos will not be totally clear, you will have like grains on it. The lowest ISO must be found, depending on the aperture and the exposure time.

Auroras can have different light intensities (from very bright to not bright) and can be either slow or fast. This involves exposure times to use that vary greatly. 2s to avoid overexposure to more than 20s if the dawn is not very bright.

The luminescence index of the auroras is between -6 EV (not bright) and -3 EV (very bright). Their light intensity will play on the exposure time. The adjustment is made in the application with the slider.

The main idea is to freeze the aurora borealis to reveal its draperies without having too much noise.

put your camera in:

• manual mode,
• RAW recording,
• self-timer (2s, 5s or 10s),
• auto white balance