Social media pages across the rural South Island have been ablaze with colour last year as aspiring astro-photographers  capture the Southern lights in breath-taking  technicolour.

Known as the Aurora Australis, this celestial phenomenon is typically rare—but this year, it has been gracing the Southern skies with much more regularity.

University of Otago postdoctoral researcher Johnny Malone-Leigh says solar storms, when the sun ejects charged particles into space, are to blame for the stunning atmospheric displays.

When the particles reach Earth, they can interact with our magnetic field and atmosphere, which Malone-Leigh says is similar to what happens inside a neon light.

"In a neon light, you have neon gas in a little tube.

"You put electricity through the tube, and the electricity excites the neon, and the neon glows."

Malone-Leigh said the same thing happens in our atmosphere: The electricity generated from a solar storm "excites" the oxygen and nitrogen in the atmosphere and causes it to glow.

"The colour depends on the atom and the altitude.

"Greens and deep reds are normally caused by oxygen, whereas pinks and blues are more often nitrogen."

The further South you go, the more likely you are to witness the aurora.

"The closer you get to the poles, the more activity you get."

"The most Aurora happen in the sea between Antarctica and New Zealand."

Climate change is not the culprit for the increase in solar storms and the resulting aurora.

Instead, the increase is all part of the sun’s natural cycle, which lasts around 11 years.

Currently at its peak, solar activity and geomagnetic storms are on the rise.

"We are seeing more of them now because stronger solar storms are coming off the sun."

The stronger the storm, the stronger it hits our magnetic field and the stronger and more visible the aurora will be across the country.

While it's easier to spot the aurora in winter because nights are longer, Malone-Leigh said that's not the best time to view the lights.

"People think it's common during winter, but it's actually more common around the Equinox."

Equinox – when the day and night are equal in length – occurs in New Zealand in March and September.

Those wanting to catch the event need to keep an eye on the KP index, which is available on aurora apps and often shared on aurora groups on social media., or if you are from Southland, Otago University's Arora Alert website.

The KP index measures the strength of geomagnetic activity in the Earth's atmosphere, ranging from 0 (low activity) to 9 (high activity).

"When you have a high KP of 8 or 9, that indicates there are big magnetic field variations globally, meaning you'll have a greater chance of seeing the aurora."

Malone–Leigh said the aurora is not generally visible in New Zealand below KP 5.

"KP 6-7, you might see a weak aurora towards the Southern horizon.

"At KP 8, we start seeing big Auroras, and at KP 9, you have a good chance of seeing the aurora even from the North Island."

By Claire Inkson