What You Need To Know
- Cameras can have long exposures and wide apertures to let in lots of light
- Image editing can bring out the colors
- Our eyes don’t pick up color very well in low light
For those of us in the mid-latitudes–that is, most of the U.S.–aurora aren’t visible very often, especially the farther south you are. And when they do show up, they’re typically not very bright.
So how do photographers snap such stunning photos?
Technology
“Cameras with long exposures will pick up on the northern lights because cameras use that long exposure of several seconds to absorb the light and colors of the aurora,” says Willard Sharp, who photographs everything from severe storms to solar storms. “Modern camera sensors are very sensitive in low light, so it’s easier to get a detailed photo of the aurora.”
Northern lights fill the sky in Edinburg, N.Y. (Photo by Derek Spagnola)
A long exposure and wide-open aperture let a lot of light in. “This allows the camera to gather data in a photo that I can then work with in Adobe Lightroom or Photoshop to bring out details and get the colors to look good and natural,” Sharp says.
“Your eyes may not catch as much color here [in the Lower 48], but the camera will do a wonderful job with that several second exposure to get a vivid picture.”
Biology
And why won’t your eyes catch much color? As great as they are, they’re just not equipped to do color at night.
You might know that your eyes have rods and cones, which are stimulated by light. The gist is that we have three types of cones that work with the brain to see red, green and blue (and all the combinations of those), but cones need a lot of light… something that the night sky doesn’t provide.
Rods are much more sensitive to light so we can see at night, but they don’t have nearly the same color abilities as cones. Sure, we can kind of see color, but it’s not at all vivid. Our eyes, like a camera, need a wide aperture and a lot of light to get the most out of what’s in front of us.
Normalized wavelengths the rods and cones of the eye are sensitive to. (CC by 4.0/Ibrahim Al-Bahadly)
Even so, “when you head north to, say, Canada, the lights are much brighter even with weaker geomagnetic storming, so the eyes can see them much more easily,” Sharp says.
Photography tips
Sharp has a “night skies cheat sheet,” if you’re interested in trying out astrophotography. And you’ll need patience. Forecasting space weather is even more difficult than Earth weather forecasts, and Sharp says looking at the data can be “daunting.”
“Sometimes a predicted geomagnetic storm will not pan out as expected. Other times minor space weather events trigger big and bright aurora displays,” says Sharp.
NOAA’s Space Weather Prediction Center has an aurora dashboard that displays current space weather conditions and aurora forecasts. Sharp also recommends SpaceWeatherLive. Here are the parameters he likes to see:
- Kp: At least 5
- Bz: At least -10 for at least one hour; two or more hours is better, and -20 suggests aurora visible to the naked eye
- Solar winds: At least 500 km/sec
- Density: At least 5, but 10 or higher is better
Conclusion
The next time you see stunning aurora photos, remember that it’s not just a matter of being in the right place at the right time. Technology and biology play a crucial role in capturing these breathtaking images. Cameras can pick up the colors of the aurora, but our eyes are not equipped to do the same. If you want to try your hand at astrophotography, be prepared for a challenge – it requires patience, knowledge of the right conditions, and the right equipment.
FAQs
Q: Can I see the aurora with my own eyes?
A: Unfortunately, if you’re in the mid-latitudes, the aurora may not be visible, or it may be too faint to see well.
Q: How do I take better pictures of the aurora?
A: Use a camera with long exposure and wide aperture, and consider editing the photo in software to bring out the colors.
Q: How can I predict when the aurora will be visible?
A: Check the Space Weather Prediction Center’s aurora dashboard or SpaceWeatherLive for current space weather conditions and aurora forecasts, and look for the parameters mentioned above.
