Photographing the night sky is a dreamlike experience, and star trail photography is highly rewarding because of the unique way in which the night sky is captured in the photograph.
A star trail occurs when you photograph the stars over a long period of time, from minutes to hours.
There are two techniques of shooting the star trails:
1. Shooting multiple, shorter length, time exposures and stack them during post-production, using Adobe Photoshop or any other software program like StarStaX or Startrails.de that will allow you to stack multiple files into one photograph. This allows us to produce a more dramatic effect in the final photograph.
2. The other technique is to take one very long exposure photograph.
Location Hunting and Planning
Planning the location for the shoot is very important. When choosing the location for the shoot you should refer the light pollution map to find the location with clear skies for the shoot. As you get further away from light polluted skies, you’ll be able to capture more stars in your photograph.
Moon Phase is the next important element to decide. Visualize how you want your final photograph to appear.
For clear skies shoot near or during the New Moon phase. With a lack of natural or artificial light, your foreground may show up as a silhouette.
If your intention is to have the star trails appear over a well-lit landscape, you’ll want to shoot while the Moon is near quarter lit. If you shoot during a Full Moon phase, the landscape will appear very bright and many of the stars will be washed out, but this gives you an oppurtinity to shoot moonscapes.
The Moon phase and its rise and set time, can be found on most weather websites, or else you can use mobile apps such as StarWalk, Google Sky Map or Star Chart.
Getting ready for the shoot
This is really important, getting ready beforehand always gives you an upper hand while shooting on a location, below are few things which will help you take better star trail photographs.
1. You need a camera that allows manual settings, for setting f/stop, ISO and shutter speed like Nikon D7100 or Nikon D810.
2. Wide angle lenses like the Tokina AT-X 11-16mm F/2.8 PRO-II DX Lens or AF-S NIKKOR 14-24mm f/2.8G ED.
3. Carry a torch with you, so you can easily see the camera to change settings while shooting at night and also help in painting the foreground.
4. Check if you have mobile apps like Google Sky Map or Star Chart installed which will help you determine where to place the camera so you get the type of star trail movement across the photograph that you want.
5. A steady tripod, to keep from causing vibrations during the long exposures.
6. Learn and practice how to lock the focus at infinity for the lens you will be using to shoot star trails.
7. Carry extra fully charged batteries for camera and flashlights, since the cold night may cause your camera battery life to be shorter than usual.
8. An intervalometer, to simplify the process of shooting the individual shots every few minutes, set your camera’s interval timer to make the consecutive images. The built-in interval timer can be found under the shooting menu. The other easiest option is to use external shutter release cable in continuous mode.
9. Carry tents if possible, if you don’t find any good foreground on the location you can use tents in your foreground for you final image.
When you reach the location, try to find some interesting foreground elements in your composition for a more interesting photograph. You should usually reserve very dark locations or places with interesting foregrounds such as tents, cars, structures…
Composite a foreground and use Exposure Bracketing to blend with the final image, this helps prevent any detail from being lost in the highlight and shadow areas of a foreground area that isn’t in silhouette.
Use mobile apps like Google Sky Map or Star Chart to help you determine where to place the camera so you get the type of star trail movement across the photograph that you want. For instance, if you center your composition on the North Star (Polaris), you’ll end up with concentric circle star trails, positioning the camera facing west will create a “falling star” look. Other compositions can produce arc shaped star trails.
Make sure the NR (Noise Reduction) is set to OFF on your camera!. Otherwise, the camera will spend equal amount of time (30 seconds) doing dark-frame subtraction resulting in gaps in your trails.
The fullness of the star trail stacking will be dependent upon whether you spend only a few minutes making exposures or are out shooting all night. If you want star circles, you’ll need to be out shooting all night and then stack the images.
While shooting remember to turn OFF the LCD display of the camera to conserve battery power.
Shoot RAW, it helps in making easy adjustments in post production.
Dont worry about the noise in the images due to high ISO, just feel free to bump up the ISO as high as you wish. Shoot test exposures to see exactly what f/stop, ISO and shutter speed (or length of time with the camera set on BULB) will produce a well-exposed image. Use the camera’s histogram to check exposures.
I use a shutter speed of 30 seconds, ISO of 800 to 3200, and with my Nikon D7100 camera and Tokina AT-X 11-16mm F/2.8 PRO-II DX lens, wide open at f/2.8 and focus at infinity.
Don’t forget to count the stars when your camera is busy capturing the frames after frames.
The best program to stack multiple files into one photograph is Adobe Photoshop , it gives you the flexibility to produce more dramatic effects in the final image.
There are many other program like StarStaX or Startrails.de which helps you with easy loading the images to create the final image
In the middle of the night clicking the stars and creatively capturing the shades of the night-sky beset with stars is a real bliss.
I want to share an amazing experience during one of our star trail shoot, the skies were crystal clear when we left for the shoot at a very serene location but just before the sunset the weather started changing drastically, thuderstorms started and we feared that it will start pouring. Thankfully it didn’t rain for almost an hour and we grabbed this opportunity. We drived to a scenic dam nearby and actually got some beautiful thunderstorm photographs.