Photographing the aurora
People who come to Churchill to see the Northern Lights are treated to a spectacular show. The experience will be remembered and talked about for years to come. It is natural for us to want pictures to remember the event. There are many problems in capturing the light of the aurora in a way that will match the actual event. I have never seen it done successfully, just as I have rarely seen photographs of deep sky objects approximate actually seeing them with your own eye. However that should not stop one from trying and I always encourage visitors to take LOTS of photographs.
Among the most difficult problems to overcome is movement in the auroral light. When the aurora is dazzling, bright, and colourful, it is also moving. A time exposure causes a blur that cannot be overcome. Shortening the time of the exposure helps, but not much. Yet, time exposures are needed to gather enough light.
A second problem one must overcome is the automatic camera. On most point-and-shoot cameras it is impossible to get a timed exposure, so cameras with manual settings are preferred. Digital cameras do a better job of registering auroral light than do film cameras. Digital cameras with 6 megapixels, a manual setting and an exposure time of at least 15 seconds are a minimum requirement. Because SLR digital cameras have a much larger CCD (the component upon which the lens focuses the light to make the digital image), SLR digital cameras are best for auroral photography. Short (wide angle) focal length lenses (12 to 18 mm.) with big aperatures offer a huge advantage in gathering a lot of light at relatively short exposure times. Also, most SLR cameras and some point-and-shoot cameras offer a bulb setting which can lengthen exposure times allowing more light to strike the CCD.
Because it is cold, cameras, batteries and people have a tendency to freeze. Additional battery packs can be switched for frozen ones during long sessions of auroral activity. Or, you can just stand back and enjoy the show!
Another concern is how to keep the camera from becoming saturated with ice and water when it comes in from the cold. I recommend a zip-lock bag. Ones with little tabs that lock the zip are much easier to use than the original zip-locks. If you keep the bag close to your body while outside, it remains pliable enough to put in your camera just before you go inside. As your camera comes back to room temperature, it will remain free of condensation.
In all circumstances, do not expect to duplicate the sight you see outside, in real time, with your own eyes. This is not to discourage you from taking pictures. They are wonderful memory joggers and keepsakes. Just remember, there is no substitute for the experience. Do not expect to reproduce the majesty of a horizon-to-horizon aurora on a 4 by 6 photograph, but do try.
In the northern lights course, there is a discussion on photography and observation. I encourage the use of any kind of binocular and I encourage you to bring both a camera and binoculars to Churchill. Like "The Observers Handbook" (the 'text' for the course), you should not leave home without them!
starman's favourite site to check on the condition of the auroral oval is www.spaceweather.com
