Light pollution is changing the world at night, but if you’re serious about astronomy and astrophotography, finding darkness often means traveling away from city lights. Here’s how to choose a good location that will help you get more from your astrophotography.
1 – Choose your subject
Where you go depends a lot on your intended subject. For example, if you’re going to set up a telescope and try for dim galaxies and nebula, then you merely need to aim for a dark sky location – and the darker, the better. However, if you’re intending on shooting astro-landscapes – landscape photography at night – then you need to identify your subject. Such images are all about composition; the subject is more the foreground of your image, not the starry background. If you want to shoot planets and/or a crescent moon, for example, then somewhere with a low western (after sunset) or eastern (before sunrise) horizon will be most suitable.
2 – Look for light pollution
If you want darkness, then go to where others are not. Figure on getting about 30 miles (50 km) away from a city. When doing so, think about the domes of light pollution that will be in your field of view from your intended location. For example, if you find somewhere dark south of Las Vegas, that city’s dome will make photographing the northern night sky difficult because your camera will very likely pick up its glow. The best way for most astrophotographers will be to consult a light pollution map and a dark site finder, though those planning a longer trip should investigate the growing network of International Dark Sky Parks.
3 – Check with the moon
If you really want to capture the light of distant stars, you need a moonless night sky. Always check the times of moonrise and moonset where you are before heading out. As a rule of thumb, the moon rises roughly 50 minutes later each night. That makes the period between last quarter moon (when our satellite rises about midnight) and about three nights after new moon (when a slim crescent moon sets soon after sunset) the best time for maximum darkness, though it does depend on exactly when you’re happy to work.
4 – Go scouting in daylight
Try not to rely on maps. There’s no substitute for driving to your intended location to check it out in advance. Find out where you should park your car, and whether the area will be accessible on the night you intend to visit. If it’s a famously dark place, then expect other astrophotographers and amateur astronomers to be there at night, particularly during well-publicised celestial events like August’s Perseid meteor shower. If so, try to use flashlights as little as possible when you return at night.
As well as familiarizing yourself with a location in advance and in daylight, it’s wise to plan some specific locations and/or compositions that you can easily return to in the dark. If you’re going to set up a telescope, then it’s probably more practical to set-up close to your vehicle, while for astro-landscapes a shot planner like The Photographer’s Ephemeris will help with angles and the position of the moon, Sun and Milky Way in your composition.