This summer many photographers will be traveling, exploring new areas and camping at their favorite parks. Most will be taking photos throughout the day and at sunset, and then putting their cameras away for the evening.
Your photography session doesn’t have to end at sunset. Many newer cameras are capable of capturing beautiful landscapes combined with the night sky. Summer in the U.S. is the best time to photograph the Milky Way, so if you can escape the light pollution of major cities and you’re fortunate to have a night with clear skies, you should be able to get some stunning images and have fun shooting under countless stars.
My favorite place to photograph at night is the Sierra Nevada and surrounding areas. My father, renowned photographer and mountaineer Galen Rowell, inspired me with the unique astrophotography he shot on film in the 1970s and ’80s. He captured moonlit scenes and star trails over Sierra landscapes including Yosemite Falls, Mount Whitney and the nearby Ancient Bristlecone Pine Forest. From 1990 to 2001, my dad and I photographed stellar events together such as the Aurora Borealis in the Arctic and the Milky Way rising above his home in Bishop, California.
Astrophotography was a shared passion between my dad and me, shaping the bond between us. After his passing, I moved to Bishop, and in 2010, I began working on my astrophotography book, Sierra Starlight.
Shooting images for the book had its challenges, including bad weather, carrying heavy loads of telescopes and time-lapse equipment at high elevations, sleep deprivation from filming all night and sometimes wild animal encounters, including a few with bears. Getting the best images required several trips to each of the numerous iconic landscapes in the region. Over the years, I captured eclipses, comets, meteors, lunar rainbows, nebulae and the stars of our Milky Way galaxy.
I’ve recently had the opportunity to test a few of the latest Nikon cameras, including the D5 and D810A. Both cameras have their advantages for astrophotography. The ISO of the new D5 can be expanded to an incredible 3,280,000. The D810A is designed specifically for astrophotography and incorporates a special IR-cut filter to allow you to shoot H-alpha nebulae at four times the contrast of a normal DSLR. Another feature that makes this camera best suited for astrophotography is that it can take ultralong 900-second (15-minute) exposures without the use of a remote.
Basic Settings for Sharp Stars
For compositions of night skies with a terrestrial foreground on moonless evenings, you’ll need to put your camera on a tripod and set your aperture to around ƒ/2.8. Depending on your camera, your ISO can be in the range of 2500 to 6400 with an exposure time of about 20 seconds. When shooting with a wide-angle lens, the exposure can be a bit longer without the stars trailing. Try several exposure times and see which result you like best.
For evenings with moonlight, your ISO can be lower, in the 800 to 2000 range, with an aperture of ƒ/5.6 or larger and a 20-second exposure. Again, when using a wide-angle lens, the exposure can be a bit longer without the stars trailing.
If you’d like to capture star trails, you can use a lower ISO setting in the 100 to 400 range, set the camera on Bulb exposure, and use a remote or cable release for exposures of several minutes or more, at apertures of ƒ/4 or larger. The longer the exposure, the longer the star trails. If you aren’t using a remote, you can use your camera’s self-timer function to trigger the shutter to minimize vibration.
On moonless nights when your subject in the foreground requires extra light, a flashlight, off-camera flash or battery-powered lantern can be used to illuminate your scene. I recommend placing a plastic diffuser in front of your source of light to avoid hot spots.
Turn auto white balance off and manually set it. I prefer 3700. Experiment with different settings to see which you like best—this may vary from image to image. If you shoot RAW files, you can always adjust this later.
Focusing in the Dark
Turn autofocus off and focus manually. If your foreground subject is 20-plus feet or farther away, set your focus to infinity. If your subject is closer, you can use a spotlight to illuminate it as you focus and take a shorter test image at a higher ISO to check your focus. You can also use Live View mode to set focus if your camera has this feature.
Leveling Your Camera
Achieving a level composition in the dark by eye can be a challenge. To compose a level horizon in your nighttime images, you can use your camera’s virtual horizon feature, if available, or use a small bubble level in your camera’s flash hot-shoe. Some tripod heads also offer a bubble level.
Deep Space Imaging
The Earth rotates 15 degrees every hour, so in order to track distant galaxies and record the faint light of nebulae, your camera has to be moving on a motorized equatorial telescope mount. The mount must be polar-aligned (keeping it centered on the north celestial pole, which is near the North Star, Polaris). You can attach your camera with a telephoto lens directly on the mount with a bracket.
Another technique is known as “piggybacking,” where your camera and lens are mounted on top of the optical tube (telescope tube lens) with a bracket. The most popular method is connecting your DSLR without a lens directly to an optical tube and imaging through it. When using these techniques, you’ll have to properly balance your mount with counterweights to avoid drift in your tracking, which could blur your images slightly. When tracking for more than a few minutes, you’ll have to use an auto-guider to avoid oblong-shaped stars. Use lower ISOs for longer exposures and higher ISOs for shorter times.
For several years, I’ve used Celestron telescopes, and I’m honored to have been chosen recently to be a member of Team Celestron. Their state-of-the-art computerized equatorial mounts and EdgeHD optical tubes are designed for astroimaging. For more info, go to celestron.com.