Aurora: what is it and where to watch it?

The northern lights are one of the most beautiful natural phenomena on our planet. Imagine that you are observing multi-coloured pulsating glows of great length (up to 3000 km) as if someone had painted the sky in swaths of bright colours with a huge brush. The spectacle is mesmerizing, and it looks like magic. In fact, the aurora is a unique but quite understandable and predictable atmospheric phenomenon that can be observed with the naked eye. Let’s find out what causes aurora, as well as where and when it can be observed.

Why is it called Aurora?

The phenomenon was named after the goddess of the morning dawn in Roman mythology. The ancient Romans believed that Aurora brought light to the gods and people, so they depicted her with a solar disk, a halo or a crown of rays around her head, or a burning torch in her hands, with which she lit up the sky with reddish-pink lights, announcing the approach of the Sun. The nature of Aurora, as a phenomenon, looks much more prosaic.

How is Aurora formed?

The sky glow effect is due to the presence of a dense atmosphere and magnetosphere on our planet. When the solar wind reaches the upper atmosphere, its charged particles interact with the magnetosphere, and free electron flows begin to move towards the poles. This is why the aurorae are also called the northern and southern lights. Due to collisions with particles of the solar wind, the atoms of atmospheric gases lose their electrons, and excited ions emit photons of light of different wavelengths.

How are northern lights formed is affected by solar activity. During strong space hurricanes, the outbreaks are larger and stronger. The most common aurorae are observed at the peaks of the solar cycle (every eleven years) and within two to three years after them.

By the way, the Earth is not the only planet in the solar system on which such phenomena occur. Scientists have recorded them on all other planets except for Mercury (there, the atmosphere is practically absent). And on Saturn, aurorae are the highest — 1200 km – due to a strong magnetic field.

What are the two types of Aurora?

Aurorae are subdivided into diffuse and discrete. The first looks like a glow in the sky, which can be seen even during the day. The second ones differ in brightness, but they can only be detected at night.

Also, they differ in colour. What colour are the northern lights depends on the planet’s atmospheric composition. On Earth, most of them are in the visible spectrum. At altitudes of about 80 km, where there is more oxygen, yellowish, green, and red hues are usually observed. Above, up to 300 km, where nitrogen predominates — purple, blue, and violet. Mars and Jupiter polar aurorae, thanks to hydrogen, are ultraviolet. But on Venus, they are bright and diffuse spots of various shapes and intensities, affecting the entire planetary disk. So the auroras on Venus are not exactly polar. More specifically, they are not polar at all, and they are most clearly visible on the night side of the planet.

Predicting Aurorae

There are several large institutions involved in forecasting such phenomena. One of the best projects, AuroraWatch UK, uses unique SAMNET and AuroraWatchNet magnetometers to measure geomagnetic activity.

All predicting aurorae processes are automated, which allows service users to understand exactly when the aurora will be visible from the UK with a high degree of probability. You can follow the information provided on the site or use the application of the same name, the data for which is provided by Lancaster University.

How to photograph the northern lights

The best time is at night. What do the northern lights look like in pictures depends on the  camera type and quality. It is advisable to use a reflex camera with a good lens and set the following settings:

• Aperture ─ not less than f / 2.8 (maximum possible);
• ISO ─ from 3200 to 8000;
• White balance ─ 3500K;
• Exposure ─ depending on the activity of the radiance: 1 ─ 12 seconds.

The faster the picture changes, the faster the shutter should work. Use only manual focus and reduce the display brightness to a minimum for a more realistic effect. Shoot in RAW format, and turn off noise reduction at slow shutter speeds so you don’t miss a single detail.

When is the best time to see the northern lights?

The northern lights phenomena usually occur in early autumn and spring, so go on a photo hunt in September or October, or in March or April. The winter is a fine time, too. It lasts long in the North, so you can see even the faintest glow in detail. The best time to watch it is midnight.

Where Can You See the Northern Lights

The celestial phenomenon is best seen near the magnetic poles. As a rule, aurora zones are located at a distance of 10-20 degrees from the Arctic Circle, and during geomagnetic storms, they spread to lower latitudes.

When can you see Northern Lights in Iceland

During clear skies here, simply pointing the camera at the Northern Hemisphere is enough to capture this phenomenon in the frame. The best time for observation is from September to March. Aurorae are most often seen during the equinoxes, when the solar wind is directed at an optimal angle to the Earth. Arrive about five days before the new moon for the most impressive shots.

When is the best time to see northern lights in Norway

Here, you can catch the phenomenon from late September to early April. The best months to shoot are September and March (early autumn and late winter), as the sun will be at its peak. You can come in the summer, too — preferably to the northern regions. As for the best viewing time, the most beautiful views are seen a couple of hours before midnight.

Where can you see the northern lights in the UK

Scotland is obviously the best place to witness the aurorae, but England and Wales can also host some spectacular light shows.

England

The northernmost county is known to have the darkest sky. This makes Northumberland an ideal spot for aurorae sightings. It is most often observed near Berwick-on-Tweed and over Kielder Park. Even if you are not lucky to see the aurorae, you can still enjoy the view of the starry sky and the Milky Way with the naked eye.

There are observed cases of northern lights in Oxfordshire areas. Even if not at its full glory, this phenomenon will still look quite harmonious against the backdrop of a rather stark local nature. Well, if you visit Exmoor National Parks, The North Yorkshire Moors, Danby and Sutton Bank, or the Astronomical Society’s Scarborough and Ryedale Observatories in Dolby Forest, you may have much better luck.

Wales

There are cases when the northern lights appeared over the Brecon lighthouses. In general, the entire Brecon Beacons National Park is ideal for observation, as it has been declared an International Dark Sky Sanctuary. Come to Wales in early autumn or early spring and book a special tour that starts in Libanus. You will watch the stars and, quite possibly, become a witness to this beautiful phenomenon.

Where in Scotland can you see the Northern Lights?

The further north you head, the more likely you are to see the Northern Lights, so Shetland is the perfect place to observe this phenomenon at its best. You can also go to Aberdeenshire, Tomintoul or Glenlivet, the Inner Seas coast, climb the mountains of the Cairngorms or Arthur’s Seat in Edinburgh Holyrood Park. The complete absence of light pollution in these areas gives a unique opportunity to capture aurorae at their best, with all the nuances and modulations.

But the best way to observe the aurora is from space. And it’s not a joke. From orbit, auroral ovals are constantly visible; moreover, you can watch them simultaneously and over large territories, both in the northern and southern hemispheres. All that’s left is to wait until space tourism becomes commonplace so that we can enjoy this miracle in all its glory. But this is a topic for another article.