While not as popular and well known as their Northern counterparts, it is possible to see the Southern Lights or Aurora Australis. The lights are caused by interaction between charged particles from the sun and the earth’s magnetic fields – centred on the poles. It just so happens it is much easier to get further North than it is to get South. Norway, Iceland, Canada, Alaska for example sit in the vicinity of 2,000km from the North Pole. While Tasmania and New Zealand are about 5,000km or Argentina and Chile are about 4,000km. Despite this difference the Southern Lights are regularly photographed from New Zealand. The secret, our dark skies with limited light pollution.
The Science behind the Aurora
The first scientist to correctly hypothesis how the Aurora works was a Norwegian Kristian Birkeland. To prove his theory, Kristian designed a surprisingly simple experiment, and by describing this experiment we can understand the aurora.
He put a spherical magnet in a box to simulate the earth and her magnetic poles, and made the atmosphere nice and thin by sucking out the air. Then he shot charged particles or ions (negatively charged electrons and positively charged protons) at the sphere and showed how they created a glow around the magnet’s poles. The magnet is earth, the charged particles are plasma being released from the sun. Charged particles are affected by magnetic fields and get pulled towards the magnet’s poles colliding with the particles in our atmosphere. The energy released from these collisions is what we see as the aurora. The closer the ions get to the earth´s surface the denser the atmosphere, the more collisions can occur. The more particles sent from the sun and the faster they travel increases our chances of seeing the aurora, the location, colors and brightness.
When is the best time to see Aurora?
In Winter the hours of darkness are longer, giving you more opportunity to see aurora. I would argue however you are better trying to see them in Spring and Autumn for several reasons.
Firstly these times of year give you more daylight for doing other activities. An expedition solely to see the Southern Lights is likely to lead to disappointment. Aurora sightings and even photos are relatively rare in New Zealand. The longer darker nights mean more driving on dark icy roads also. There is no evidence that temperature affects the likelihood of seeing the lights – the temperature 80 or 100km above the earth is completely different to the surface. Conversely in summer the dark hours are hardly long enough to have a good opportunity either.
Secondly is something called The Russell-Mcpherron Effect. Aurora are more likely to be visible further from the poles during the equinox. One theory is that magnetic fields are more aligned with the solar wind at this time. Even without notable solar wind from the sun Aurora are reported stronger and further from the poles than would normally be expected during this period.
It is no coincidence that astrophysicist, Ian Griffin schedules the ´Flight to the Lights´ for March. No surprise one of the biggest nights of 2017/18 season was the 8/9th of September when the lights were visible to the eye in Glasgow and Dunedin. In fact, a quick review of news articles about seeing the Aurora in New Zealand shows a definite bias in September and April.
The aurora is not predictable far in advance, some phenomena on the sun may give us about a 1 month warning that there may be some activity. Some satellite inputs may give an indication about 3 days out. Increasingly we are getting better at using near earth satellites to predict aurora about 45 minutes before they occur. One thing we can determine is the moon. Photographing in the arctic circle, I love moonlight to bring out the landscape. In New Zealand, the aurora are typically so faint that a little moonlight can be a big issue.
To conclude and to set your expectations. As an aurora enthusiast, I successfully see the aurora with my eyes, about once a year. I photograph it at various strengths about half a dozen times a year – this is not for lack of trying. If I was unemployed and willing to travel significant distances to avoid bad weather and didn’t need to sleep at night, I’m sure I could triple or quadruple these figures. Realistically as you are travelling around New Zealand with activities to do, a time limit and weather to compete with, your likelihood of seeing this incredible phenomenon is very slim. But it is not impossible, join Facebook groups, download monitoring apps, keep an eye on the weather and you may encounter an incredible experience. Get out and enjoy the brilliantly dark skies New Zealand has to offer and see the Milky Way. If you don’t succeed at least you have an excuse for another holiday, either to New Zealand or perhaps somewhere in the Arctic Circle.
Good Luck!
- Glendale App
- Dunedin Aurora
- Southern Hemisphere Aurora Group – FB
- Aurora Australis (NZ) – FB
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