A few years ago I saw a photograph of star trails swirling over mountains. It was such a mesmerizing shot that I had to learn how to do it myself. This tutorial will teach you the basic steps, but getting out there and learning from experience is always the best way to master the process for yourself.

Stuff to bring:

1. Camera capable of long exposures. (Bulb Mode)
2. Sturdy tripod
3. A wide lens that allows you to compose your shot in the dark. A few examples: 16-35mm f/2.8; 24-70mm f/2.8; 35mm f/1.4; 50mm f/1.4
4. A shutter release cable or remote trigger. Most cameras only allow timed exposures of 30 seconds max, so you'll need the ability to customize the exposure time to fit your needs.
5. Warm batteries. Cold batteries don’t last nearly as long as warm ones, so keep those puppies toasty until you’re ready to shoot. (An A/C adapter can also be helpful if you’re near a power source)
6. A Jacket. It gets chilly at night!

Step 1: Go where the stars shine. Get as far away from people and light as you can. If you live in a big city, this can be tough due to high levels of light pollution. My favorite place to shoot stars is in a little Colorado town called Oak Creek. It’s so dark there on a clear night that you can see the Milky Way with your naked eye.

Step 2: Keep the moon in mind. The moon is brighter than you think. If you don’t plan accordingly, an overly bright moon phase can ruin your exposure. There are a few cool apps out there to help you schedule your star trail shot. Star Walk is probably my favorite, as it’s for both the iPhone and iPad and is crazy fun to use outside in the dark. If apps aren’t your thing, you can look up the moonrise and moonset times for your area here. A full moon will be way too bright, while a new moon may not provide enough light for the foreground of your image.

Step 3: Wait out the red eyes. Most commercial flights are safely on the ground by 11:30PM, but as a rule I like to wait until 1:00AM to start shooting. If a plane does fly through your shot, you’ll see a super-noticeable straight streak that can be annoyingly tedious to remove.

Step 4: Prep your camera. Remove anything extra from your camera’s body, such as straps that can catch the wind.

Step 5: Format. Shoot star trails in RAW. It’s the easiest and most forgiving format when it comes to correcting levels and tweaking the white balance. If you’re not super familiar with RAW, shoot in RAW + JPG, as you’ll always have the RAW as a digital negative in case you want to go back later and tweak things a bit.

Step 6: Camera Settings and Focal Distance In general, shooting at ISO 200 with an aperture of f/4.0 or f/4.5 will do nicely. When focusing, it’s safe to set your focal distance at infinity, but if you’re not sure how to do that, you can auto-focus on the moon and then toggle your focus setting to manual.

Step 7: Exposure Time. Don't attempt to capture star trails if the moon is more than half full. It's just too bright. When there is a half moon, you’ll want to shoot for up to 25 minutes. When there is a new moon and the sky is completely dark, you can leave the shutter open for up to 125 minutes without over-exposing. Reminder: Leaving the shutter open longer is almost always better than ending the shot prematurely, so don’t sweat it if you go slightly beyond these benchmarks.

Step 8: Hunting Polaris. If you want your image to show complete circular trails, you’ll need to find Polaris, the North Star. To find Polaris, just draw a straight line up from the ladle-edge of the Big Dipper and you’ll see it as the end of the handle of the Little Dipper. Having Polaris in the frame gives the shot a neat sense of the Earth spinning like a top. If you need extra help finding Polaris, check out this site.

Step 9: Stay dark and go away. Unless you are painting the foreground with light to compensate for a new moon, keep all flashlights away from your camera. Accidentally flashing a bright light at or near the camera can ruin your shot. Also, stay away from your setup, as the likelihood that you’ll bump the camera is quite small if you’re physically not near it. There is nothing worse than bumping your tripod and having to start over.

I hope this gives you enough to play with, and please share your experimental star trail shots with us on facebook!

Happy shooting,
-Dustin