Capturing The Amazing Aurora

January/February 2012 by Nigel Fearon

It’s still summer and we’re camping. The night is just starting to get dark enough to see some stars and, more importantly, the Aurora. The chase begins as I lock down my tripod, pointing my camera west, opening the shutter and the lights quickly flutter to the other side of the sky. Sometimes slow moving, sometimes as fast as lightning — no two nights are ever the same.

As we quickly approach 2012, our eyes turn North to gaze into the night sky, awaiting a natural wonder that is beyond imagination — Aurora Borealis, the Northern Lights. Over the next two years we can expect a show that is more intense and more active than it has been in recent memory — certainly than has been recorded by digital photography. Welcome to the maximum of Solar Cycle 24, ultimately peaking in the summer of 2013 when the Aurora may be seen as far south as California or Florida.

Currently we are two years into the solar cycle and heading into the solar maximum — the most active period of the 11-year solar cycle. This international event has captured the interest of the scientific communities, shown by the creation of the AuroraMax research project, a partnership between the Canadian Space Agency, University of Calgary, City of Yellowknife and Astronomy North. AuroraMax is a great effort to study the lights, but also an excellent resource for people around the world to share in our experience, thanks to the AuroraMax camera.

To some, the Northern Lights are phenomena veiled in mysticism, an unearthly spectacle only understood by scientists. But the explanation of the lights is really not that complicated. The sun constantly emits highly charged particles, called solar wind, streaming at the Earth at speeds around 1 million miles per hour, yet still taking 40 hours to reach Earth.

When these particles reach Earth’s magnetic field, the electrons and protons are hurled towards the Polar Regions where they react with atoms and molecules in the ionosphere, 100 to 600 kilometres above Earth. As energized electrons collide with oxygen atoms, energy is released in the form of an electric green light, the Aurora’s most common colour. On nights of higher activity, the solar particles will react somewhat differently with oxygen in the upper ionosphere, creating reds in the Aurora.

In my experience, this is often seen at the top edge of a band of green. I have yet to witness the stunning completely red Aurora I have seen in some photographs… but I am keeping my fingers crossed for this year.

At the peak of activity, the Aurora will also come alive with blue, purple and violet colours as particles interact with nitrogen 80 to 100 kilometres above Earth. These reactions all take place along the Auroral Oval, a band that encircles the Earth at the North (Aurora Borealis) and South (Aurora Australis). The bands are centred around the Earth’s magnetic poles and expand or contract according to the magnitude of the solar wind. The incredible dance that we witness is due to the fluctuations in atmospheric current.

Predicting the imminent arrival of the Aurora and anticipating their possible shapes and intensities is tricky business indeed, not unlike predicting the weather. However, a number of signs indicate a great night of Aurora. One is the occurrence of a sunspot facing Earth. Another is a solar flare or a coronal mass ejection (CME). Once these events occur, the activity on Earth can roughly be expected 40 hours later. Many resources are available for Aurora predictions.

In Yellowknife, we have our very own forecaster, thanks to dedicated Aurora and astronomy enthusiast James Pugsley: Like the weather, I take these predictions with a grain of salt. Each evening I watch for the Aurora (I am lucky enough to see them from my back window and deck). Then, if I see the faintest hint of Aurora, I grab my gear and head out of town away from light pollution.

The first job is to find an interesting spot to take photos of the Northern Lights out on the land. Really this means finding a location that is facing the right direction — Aurora typically follow a line from east to west — that also has something else interesting in the foreground. In the summer and fall, water is a favourite element to include in a photograph, since it magnifies the presence of the lights with a stunning reflection. Other favourites include trees, which are more typical, and cliffs, to create interesting geometry with various shapes. Houseboats, old vehicles, the city or even an ice-castle are great elements to include, in Yellowknife anyway.

Once a stunning foreground element is chosen to anchor the image, I set up my tripod, the first crucial ingredient to successful Aurora photography. Next is the camera. Unfortunately, capturing the Aurora often requires a high-end digital SLR for the best results and always have the quality set to RAW. This allows your photos to retain the most information and quality. JPEG is possible, but you basically loose the ability to edit the photos. Film is certainly possible, but at ISO speeds of 1600 or greater, results are often grainy and of lesser quality. With RAW photos, white balance is easy to adjust on the computer, but if you’re shooting JPEGs, then setting your white balance to “tungsten” is a good starting point.

With camera mounted securely, you’ll want to go for a good wide-angle view, ideally 24 mm and wider. Personally my preference is a regular wide-angle over the fisheye, since it distorts the land less, but the benefit of a fisheye is that you can capture the whole sky with the 180º field of view.

In terms of aperture control, your setting should be wide open. For the DSLR crowd, an aperture of f2.8 is ideal. Any less than that, focusing precisely is difficult. More than that and you are not letting in enough light. Actual exposure time and best ISO rating can vary from night to night. Typically I start out at ISO 800 with a 30-second exposure, then adjust according to the strength of the lights. I prefer to not go over 30 seconds for the exposure time because once you do, the stars begin to leave trails and I think they look much better as sharp points of light.

Manually focusing your camera is often the hardest task when it’s dark and below -30ºC. There are two methods that I’ve used with relative success. The first works well if your lens has a distance scale on it. During the day, find something that is quite far away and focus on it. Take note of where the focus is, relative to the ∞ (infinity) mark. You’re essentially looking for the hyperfocal distance (there are many tutorials available for help determining this focus point). Once you find this sweet spot on your lens, then you can easily find it again at night. The other method is to use “live view” on your camera to focus. Once in live view, set your focus point on the brightest star in the sky that you can see, then manually focus until the star is the smallest, most defined point possible.

Of course the most important step is to be daring and press that shutter. For best results a cable release is recommended, but if you don’t have one of those, then simply use the timer setting on your camera. Exposure times can range from 1 to 60 seconds, so just get out there and play around. With the longer exposures you can often enjoy watching the lights more than looking through the lens, which is the best part of Aurora photography — just enjoying the spectacular show unfolding above!

Nigel Fearon is a photographer, based out of Yellowknife, Northwest Territories, and has been photographing the Aurora Borealis for three years. You can follow his adventure into the AuroraMax on his blog and more of his work can be found at