Poetry of coronal auroras

On the evening of November 12, I found myself repeating a familiar ritual of this remarkable solar cycle: packing the car with cameras, knowing that if the forecasts were correct, the night might be special. The coast looked cloudy, but inland was tipped to clear, so as soon as the car was packed, I drove the hour to my Middlemarch hideaway.

Even through patchy cloud, the southern sky carried that unmistakable glow that says an aurora is waiting in the wings. I set up cameras around my observing shed and watched as the cloud slowly thinned, revealing a pale green wash behind it. Over the next hour, the display strengthened, almost impatient to break free.

Then, just before 11pm, the sky erupted.

Rayed pillars surged upward, bright and fast, and suddenly the whole display tightened into a whirl directly above me — a coronal aurora. These are among the rarest and most dramatic of auroral forms. To the eye, the rays appear to converge overhead into a luminous, spinning crown; in truth, it’s a perspective trick, as we look straight up into long curtains of charged particles funnelling down Earth’s magnetic field lines. Still, standing beneath one, the explanation feels secondary to the sheer wonder of the moment.

Coronal auroras have captivated observers for centuries. Early European explorers wrote of "heavenly spears". The poet Hugh Brackenridge described the aurora as "dancing beams of light". Māori traditions speak of Tahu-nui-a-rangi — the great flame in the sky — sometimes interpreted as fires of ancestors guiding travellers. Under a coronal display, it’s easy to see why our forebears reached for poetry.

This is the fourth coronal aurora I’ve seen during the current solar cycle — solar cycle 25, if you’re counting. Solar cycles run for about 11 years, rising to a magnetic peak before the sun’s poles flip. They’ve been numbered since 1755, and this one has been astonishing. In the last cycle, I didn’t see a single corona; this time, they seem to be arriving in abundance.

There are signs the sun is now past the peak of cycle 25, though still energetic enough to throw surprises our way. As the southern nights warm and shorten, the next few months remain an excellent time to enjoy this splendid taoka of our sky. The storms won’t last forever — so whenever the forecast hints at activity, do what I do: load the car and be ready.