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Chasing the Aurora
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By: Howard Cheng
The aurora, named after the Roman goddess of the dawn, has captivated humankind’s imagination for generations since time immemorial. Across different cultures, storytellers of old sought to explain the aurora’s manifestation with tales of Arctic foxes running in the sky, souls of the dead playing with the skull of a walrus, or even celestial battles between dragons. Others saw the aurora as vengeful spirits or a bad omen foretelling war, disease, and famine. It would take humanity until the 1960s to discover the scientific cause of the aurora.
As part of normal solar activity, the solar wind carries charged particles from the Sun’s atmosphere into space. Events such as solar flares or coronal mass ejections increase the amount of charged particles carried by the solar wind. When these particles reach Earth, our magnetic field directs them towards the north and south poles, where they collide with gas molecules in our atmosphere, releasing energy in the form of light. As areas around the Arctic are more accessible than areas around Antarctica, the northern aurora, aurora borealis (‘borealis’ derives from Boreas, the Greek god of the north wind), is talked about more often than the southern aurora, or aurora australis (‘australis’ is Latin for ‘southern’).
The concentration of the aurora around the poles and the need for dark skies to fully appreciate the cosmic phenomenon make aurora viewing an ideal low season travel activity during the autumn to spring months. As solar activity peaks and troughs in cycles of roughly 11 years, we currently find ourselves at the peak of the current cycle. This makes the next couple of years some of the best opportunities to try and see the aurora before solar activity wanes.
What might you see if you were looking for the aurora? As you gaze upwards on a clear night when the terrestrial and cosmic weather conditions align, you might notice ethereal veils of light dancing across the diamond-studded dark of the night sky. These ethereal veils might reveal a hint of green, especially during strong displays. I still remember the excitement of my first aurora sighting. Seeing a whitish-grey mist move in the night sky, I initially mistook it for fast moving clouds. Uncertainty gave way to excitement as pointing my camera at the ‘mist’ revealed a bright green trail splitting apart the dark of night as if some otherworldly manifestation was making its way to earth through a tear in the fabric of space above us.
Photographs of the aurora often show the phenomenon in its most dramatic form, with vibrant bright green streaks painted across the night sky, because the sensors of digital cameras are more sensitive to light than our eyes, and so they can better capture fainter light than we can see. While seeing the aurora perform its dance in the night sky is no less captivating than the dramatic emerald streaks seen in photographs of the aurora, there is a certain sense of satisfaction when you are able to provide photographic evidence to your friends and social media following of having witnessed the aurora.
Alongside the photos accompanying this piece, I have set out the exposure settings which I used, along with some of my personal tips for shooting the aurora below. There is no need to follow these ideas or the settings I used slavishly - think of them as a starting point from which you can conduct your own photographic experiment as to what might work for you in terms of your own photographic style.
Equipment essentials
To capture the aurora effectively, you will need a few key pieces of gear:
Camera:
A DSLR or mirrorless camera with manual settings is ideal. Full-frame cameras offer an advantage in low-light conditions, but modern crop sensor models can also produce excellent resultsespecially if sharing on social media rather than making large prints.
Wide-angle lens:
I prefer lenses that are 28mm (full-frame) or wider, with an aperture of f/2.8 or faster. The wide field of view can capture the expansive nature of the aurora along with some of the environment.
Tripod:
A sturdy tripod is crucial for taking long exposures.
Self-timer, or a remote shutter release:
Using the camera’s selftimer function can reduce camera shake from physically touching the shutter button. If your camera does not have a self-timer function, a remote shutter release can trigger the shutter without touching the camera.
Warm clothing:
Dressing appropriately is essential for spending prolonged periods outdoors. Also consider bringing a vacuum flask containing a hot drink to help with feeling warm when spending hours outdoors in temperatures of under -20°C.
Headlamp:
A headlamp provides hands-free light for setting up your gear. Avoid using it too often as you need to allow your eyesight to get accustomed to the low light environment.
Shooting tips
Manual mode: Use manual mode on your camera to have full control over exposure settings.
Shoot in RAW: This will allow you a lot more latitude to play with shadows and highlights when you come to edit your photos to bring out that beautiful streak of light in the night sky.
Focus manually: Manually focus your lens so that the stars are as pinpoint sharp as possible.
Use a low ISO: Start with a low ISO to reduce noise. I usually like to use around ISO 800 or 1600, but do not be afraid to increase the ISO if necessary. A couple of my favourite photos of the aurora were shot using ISO 6400, and I have even used ISO 50000 when shooting the aurora from a plane during a turbulent section of the flight as I needed a faster shutter speed. Noise is also often less noticeable if you are compressing or downsizing your image for social media posts.
Wide aperture: Use the widest aperture your lens allows to allow for maximum light gathering. This can help reduce the ISO setting which you need to use.
Long exposure: Experiment with shutter speeds to capture the aurora’s movement. The shutter speed you choose will depend on your tolerance for star trails in your photograph. Do an online search for ‘NPF calculator’ (N refers to aperture, P refers to the pixel pitch of your camera’s sensor, and F refers to the focal length of the lens), which can help you identify what is the slowest shutter speed you can use for your star trail tolerance.
Use foreground elements: Include foreground elements like trees and buildings to add depth and scale to your photographs. Use the daylight hours to scout for and familiarise yourself with suitable shooting locations.
Do not forget to look up: Do spend some time to take your eyes away from the camera’s LCD screen or viewfinder. As pretty as photographs of the aurora look, it is no less captivating to see the aurora shimmer and weave against the dark.
