If there's even the slightest prospect of a display of the southern lights, I head off to a favourite viewing spot. That's why, last Friday, I was on Hoopers Inlet's shore enjoying an impressive aurora australis display.
But the photos I took with my cameras bore no semblance to what I had seen with my eyes. While I observed the pulsing beam-like structures dancing in the sky, the only colour visible during the display was pale greyish green.
One of the primary reasons cameras excel at capturing the vibrant hues of auroras lies in their enhanced ability to detect and reproduce subtle colour variations. While the human eye is a remarkable biological marvel, its visual perception is constrained by its quantum efficiency - how well it absorbs and processes light.
Our eyes encounter challenges perceiving colours in auroras primarily due to the composition and distribution of their photoreceptor cells - rods and cones. Rods, responsible for low-light vision, are highly sensitive to light but are not colour-specific. They enable us to see in the dark but cannot discern specific colours.
On the other hand, cones are responsible for colour vision and function optimally in brighter conditions. However, cones require a higher intensity of light to activate and are less sensitive to faint light, making them less effective in dimly illuminated auroral skies.
Consequently, the human eye struggles to discern the intricate hues of auroras due to the dominance of rods and the relatively dim lighting conditions. This is also why some people, inspired by the incredible photographic colours of the southern lights, are disappointed when they first see an aurora.
But don't lose heart. I've seen colour (primarily reds and greens) in about one-third of the displays. And in my opinion, you don't need to see colour to be inspired by this beautiful natural phenomenon.
