Light pollution and aurora photography
Light pollution may cause several problems for aurora photography. What are these problems, and what can you do to avoid them?
Heavy light pollution from urban arias
When geomagnetic activity is high, even big city lights can't prevent you from seeing the brightest parts of the aurora in the sky. But heavy light pollution creates a glow in the sky. That glow washes out the dimmer parts and diminishes the vibrant colors and details of the aurora.
The best you can do is choose a location with relatively low light pollution. Use the light pollution map to find areas with a reasonably dark sky (green, blue, or grey areas on the map).
If you plan to take a picture of lovely cityscape with northern or southern lights in the background, choose the nights with the clear sky and dry air. These conditions will reduce the glow from the artificial lights and their effects on the aurora visibility.
Clouds illumination
Suppose you manage to find an area with a relatively dark sky. The light from small distant villages or towns can't create enough glow to affect the aurora. But their artificial light can illuminate clouds above them that usually don't look good in the pictures. If the weather forecast predicts partly cloudy conditions, try to find a location where you can avoid such illuminated clouds in the frame.
Headlights
The car's headlights are very bright, particularly on moonless nights. They can't affect the aurora directly but can ruin your photos by chaotic illumination of mid-ground. So, try to avoid roads with night traffic and parking places where somebody could stay long with headlights on. If your photo was ruined, take other shorts of foreground and mid-ground and replace necessary parts in post-processing.
Artificial light in the frame
In some cases, minor artificial light sources can improve your images by adding points of interest to your composition. Remember that any light source at night becomes a dominant element in the picture. Consider its color temperature, position in the frame, landscape illumination, and shades it produces.