Over the past few days, intense solar activity has once again brought attention to one of the most spectacular natural phenomena, the aurora borealis. Images shared from various points on Earth are consistent with magnetic storms being monitored by space agencies, and information published by some European scientific institutions suggests they could be felt even at lower latitudes than normal, as in Spain.
This increased visibility is no coincidence. The National Geographic Institute (IGN) explains that geomagnetic storms caused by the arrival of charged particles after solar eruptions can strengthen and expand the range of auroras, and in certain episodes they can appear outside the polar regions.
In this context, those who tried to photograph this phenomenon may have noticed a difference between what they saw with their naked eyes and what they captured with their mobile cameras. Experts from NASA and Aurora Reykjavik explain why recordings from both the human eye and digital sensors don’t always match, and what factors determine this difference.
What are auroras and why do they appear during solar storms?
According to IGN, auroras occur when large amounts of charged particles from the sun reach Earth after a solar flare or coronal mass ejection. These particles are deflected by the Earth’s magnetic field to regions near the poles, where they come into contact with gases in the upper layers of the atmosphere.
This shock causes the emission of light, hence the appearance of auroras in the Northern Hemisphere and Southern Lights in the Southern Hemisphere. The gases with which they interact determine their color. NASA explains that oxygen typically produces shades of green and red, while nitrogen produces flashes of blue or violet.
Auroras are often seen at high latitudes, but IGN reminds us that during severe geomagnetic storms they can also be seen far to the south. An extreme example is the Carrington phenomenon of 1859, when aurora borealis were observed throughout Europe, Central America, and Hawaii, and there are historical records in Spain.
What the human eye sees and what the camera captures
One of the most common questions is why the aurora borealis appears faint or whitish to the naked eye, but appears as an intensely colored display on a mobile phone. Aurora Reykjavík explains that while it is possible to see the Northern Lights with the naked eye, “the ability to experience their full beauty depends on the strength of the phenomenon, light pollution, and viewing location.”
The main difference is how our eyes work and how cameras work. NASA points out that mobile sensors can accumulate light for several seconds with long exposures, which is impossible for the human eye. This causes the camera to produce images that are more saturated, brighter and sharper than we actually perceive.
Additionally, in dark situations, digital sensors tend to intensify green and purple tones, while the human eye tends to primarily discern soft greenish light. Therefore, on nights when the aurora is weak, the camera will see colors that observers cannot perceive.
Where to see best and factors that affect visibility
Location is a determining factor, and the higher the latitude, the greater the chances. Iceland, Norway, Finland or Canada are located under the so-called “auroral oval”, a circular area around the poles where the phenomenon appears regularly. The Northern Lights Reykjavik is a reminder that Iceland’s low light pollution allows for clearer observations.
Still, extreme geomagnetic storms can extend the ellipse to mid-latitudes. This explains why, in very specific episodes, the aurora can be seen from areas of Europe where it normally does not appear.
Visibility also depends on the Kp index, an international measure that reflects geomagnetic activity on a scale of 0 to 9. According to NASA, the higher the value of the index, the more likely the phenomenon will be visible in areas farther from the poles.
How to photograph the aurora borealis without misleading images
NASA offers several recommendations to help cameras capture realistic images of phenomena without “inventing” too many colors. among them:
Reduce the exposure time slightly to avoid saturation.
When shooting at night, use a tripod to prevent camera shake.
Try a lower ISO to minimize image noise.
Please keep it away from artificial light sources to avoid changing the color tone.
Aurora Reykjavik also advises observing the sky in open, dark areas and being patient. This phenomenon can intensify or disappear in a few minutes.
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