- Posted July 30, 2013 by
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Your views of stars and space
Fire in the sky
- dsashin, CNN iReport producer
Like most people, when I thought of the Aurora Borealis, it was always in the context of a snow draped forest and majestic peaks silhouetted against the brilliant, colorful chaos of a sky awash in swirling light and color. As a matter of fact, it just never occurred to me that one might view this amazing natural light-show south of the arctic until I saw a set of images taken by fellow Times Argus photographer Stefan Hard. As I look back, I now realize that was the moment my obsession with the Northern Lights took root.
The process of photographing the Aurora is, as it turns out, not all that complicated. With a little luck, research, advanced planning, a tripod, a wide angle lens and a relatively modest camera equipped with a manual exposure mode, anyone can capture Mother Nature’s preeminent light show.
The aurora is caused by the collision between charged particles ejected from the sun and the Earth’s atmosphere. When the particles from the sun collide with material that makes-up the Earth’s atmosphere, energy, in the form of light is released which we see as the aurora. Because most of the particles ejected from the sun are deflected by the Earth’s magnetic field, the phenomena is generally seen in the far North and far South near the poles where the Earth’s magnetic field is weakest. The best chance to see the aurora is following a coronal mass ejection, which happens when a large mass of plasma and other material are blasted out into space in the direction of the Earth.
The first step in photographing the Aurora is knowing when it may be visible and active (combined with a healthy dose good luck). Fortunately, for those who do not have a satellite continuously monitoring the Sun’s activity, a number of websites and apps are available to keep hopeful sky watchers abreast of potential aurora activity. Online resources include www.softservenews.com, www.spaceweather.com, www.aurorahunter.com and www.swpc.noaa.gov/pmap/pmapN.html. Some handy apps available to help the new aurora photographer are “Aurora Forecast” available for both IOS and for Android. Another handy app which provides a quick overview of the current state of the Aurora is “Aurora Buddy” which is available for the Android operating system.
The activity level of the aurora is measured by the “KP Index” on a scale from 0 to 9, with 0 being the lowest activity level and 9 being the highest. Because the Aurora is not evenly spread across the sky and tends to clump in pockets, the KP Index is an average of a number of observation stations spread across the hemisphere. For the aurora to be visible as far south as Vermont, the KP level generally needs to fall between 4 and 9. The higher the index, the further south the lights are visible.
Once it becomes clear the aurora is active, the next step is finding a good location for observation and photography. The best spots are located away from sources of light pollution like cities and towns. It is not a bad idea to scout potential locations during daylight hours noting the site for those times when the aurora is active and visible.
Once one arrives at the chosen location, it is important to set-up the camera and tripod so they are facing north / north-west. Depending on how energetic the aurora is, visibility may range from very faint and not visible to the human eye to very bright and downright spectacular. When the Aurora is very faint it may be completely imperceptible to the human eye, this does not, however, mean it cannot be photographed.
To make sure the light-show is in focus, put your camera in manual focus mode and set the lens focus to infinity. This is the little figure eight symbol that appears on the lenses distance scale when the focus ring has been rotated all the way to the right.
For exposure settings, I usually start with the aperture set to f5.6 and an exposure length of 20 seconds. Depending on the conditions, one will want to vary the aperture and length of exposure.
As with most photographic endeavors, ultimate success is going to be realized through patience, experimentation and most important getting out and taking pictures.