In Search of the Aurora

No matter how many times you see them, the northern lights, or aurora borealis, are an ethereal, breathtaking sight. Dancing silently in Earth’s upper atmosphere, they form iridescent sheets of green and red (or sometimes blue and purple) light. Common in polar and sub-polar regions, auroras can sometimes be visible at lower latitudes, including recent dazzling displays as far south as Northumberland.

What are the northern lights?

The northern lights are caused by the interaction of gases in Earth’s atmosphere with solar wind: a stream of electrically charged particles, called ions, that shoot out from the sun in all directions. When the solar wind reaches Earth, it slams into the planet’s magnetic field, producing currents of charged particles that flow toward the poles. Some of the ions become trapped in a layer of the atmosphere called the ionosphere, where they collide with gas atoms and ‘excite’ them with extra energy. This energy then gets released as particles of light or photons.

Where can you see the northern lights in Northumberland? 

To witness the northern lights you must be somewhere where the skies are dark, clear and far from light pollution. At 55 degrees latitude north and home to a 150-square-kilometre gold-tier dark sky park, Northumberland is widely regarded as the best place in England to see the northern lights. Located high up on Black Fell, commanding unobstructed views over the remote Kielder Forest, Kielder Observatory is one of the best places in the county to view the phenomenon. The observatory even runs dedicated ‘aurora nights’ when guests can learn more about the spiritual stories surrounding the aurora and the fascinating scientific facts that explain it. As most aurora displays in the United Kingdom are only visible low on the northern horizon, the Northumberland coastline can often be the best place to go searching for the aurora. On the coast, facing north, you’re looking out over the North Sea, which provides an unobstructed northern horizon void of light pollution.

Is it possible to predict when a display will occur?

Some years see more auroras than others, and this is because sunspot activity waxes and wanes on an 11-year cycle. The cycle typically consists of two phases, the solar minimum and the solar maximum. During the solar minimum, the sun experiences fewer sunspots and is generally less active. Conversely, during the solar maximum, the sun's magnetic activity intensifies, resulting in more sunspots, increased solar activity, and more auroras. The most recent upward trend began in 2019 and was initially forecasted to peak in 2025. However, more recent studies now predict the peak could hit us a year early. If correct, 2024 could be a fantastic year for the aurora in Northumberland, with an increased frequency of brighter displays.

How can you check what the aurora activity is? 

Several real-time apps and websites exist to better understand the chances of seeing a display. Popular apps like SpaceWeather Live and Glendale Aurora Alertsare essential tools for those chasing the aurora. The apps include key statistics like substorm status, solar wind speed and density, the orientation of the interplanetary magnetic field and live maps of the United Kingdom showing where others have successfully witnessed the northern lights. Another effective way to understand aurora activity is to join dedicated social media pages, such as Aurora Groups on Facebook. These platforms can provide a daily overview of the likelihood of a display as well as live insights and images posted by members of the community.

 What can you expect from an aurora display in Northumberland? 

Whilst witnessing the aurora is an unforgettable experience, photographs of the northern lights often lead to inflated expectations of what a display might be like. In Northumberland, most auroral displays are faint and colourless to the naked eye. Our eyes are not as sensitive to colour in low-light conditions, and only the most active displays allow us to see pale green and purple hues. A modern camera’s long exposure setting allows it to capture light over an extended time period. Capturing more light reveals a much brighter and more colourful display that isn’t possible to see with the human eye.

How to capture the northern lights 

 The advancement of smartphone cameras has increased the ability to capture night sky and northern lights images. Using night modes or dedicated night photography apps enables your phone to take long exposures. This is probably the easiest way of checking if there’s a faint display that your eyes can’t quite grasp. For better results, a DSLR or mirrorless camera paired with a wide-angle lens and tripod will produce higher-quality photos.

 Three fundamental elements in photography control the exposure of an image: shutter speed, aperture, and ISO. These settings can be adjusted to control the amount of light that reaches the camera sensor, to achieve a well-balanced aurora image.

 Shutter speed – This is the length of time the shutter is open to light. A slow speed means the shutter speed is open [NS3] for a longer duration than a fast shutter speed, allowing for more light to be captured. During a long exposure, the camera can record movements and changes of light over time which can result in blurred images. This is why a tripod is required to keep the camera still. The dynamic movement of the aurora is surprisingly quick. I usually recommend keeping the exposure time to a maximum of ten seconds to preserve good structure within the lights, but some setups and conditions may require longer.

 Aperture (f-stop) – Aperture refers to the width of the opening/pupil within the optics, which can be adjusted to change the focal ratio of the lens. A wide pupil will allow more light to reach the sensor than a narrow pupil. Within the camera settings, the aperture is expressed as ‘f’ followed by a number. The lower the f-value, the wider the aperture will be. I’d recommend in most situations to use the widest aperture your lens can achieve; this will allow you to keep the exposure time as short as possible. Just be aware that some lenses may cause very obvious optical aberrations when at the widest aperture.

ISO – This setting is another way of controlling the brightness of an image. Cameras can amplify light captured by the sensor, making the image brighter. The higher the ISO number, the more amplification is applied. Typically, in astrophotography, higher ISOs are used compared with other types of photography. It’s tempting to use very high ISO settings, but this can cause unwanted issues with image quality. More amplification introduces higher noise/grain, resulting in a loss of detail and colour. I would recommend trying to stick to the rule of no longer than ten seconds, with the aperture wide open, then adjusting the ISO accordingly to achieve a well-exposed image. However, this depends on the ability of the equipment used. If the image is too noisy, then you may need to decrease the ISO and increase the exposure. It’s all about trial and error, and balancing the pros and cons of the three settings to achieve the highest quality image your setup is capable of.

Words & photography by Dan Monk