Photographing star trails

Photographing star trails

Here I will talk about how to photograph star trails. I did this recently as I was trying to capture the Perseid meteor shower with limited success. Star trails are nice though! I’ll go through the steps I took below. To start make sure you have a wide angle lens with a wide aperture so your camera can get a lot of light. I am using this lens, the Sony FE 20mm f/1.8 G. I am using a Sony a6000 E mount camera that works with this lens. You also must use a tripod to do this. On to the steps!

  1. Find a site that you think would be nice. It is really helpful if there is an interesting foreground in the frame of the photo that aren’t all stars for framing. The foreground needs to be lit in some way if you are doing everything at night! ***Bonus Points*** have the north star (for the northern hemisphere) in some cool way in your frame so the stars appear to move around it. Or have the scene set so that the motion of the stars complement your foreground.
  2. Find a dark night free of clouds and most of the moon (you can plan for the moon but clouds can be more luck of the draw).
  3. Find some location where you can leave your camera up for an hour+ to make sure you have enough time to capture the trails
  4. Manually focus on a bright object in the distance. This can be challenging depending on time or place, I have used the moon and some yard lights in the past. I imagine a bright planet would work too. You want these far objects to be as sharp as possible before trying to taking pictures.
  5. Set your film speed (ISO) to something reasonable (I used an ISO of 1000). I wanted the photo to be sharp and not have a lot of noise. I haven’t studied this in depth though.
  6. Set up your camera to take a photo every X seconds. Choose X wisely depending on how bright or dark you want your photo to be in the end. Make sure X isn’t too long! Otherwise the stars in the frame will streak during X.

As I mentioned, I took a bunch of photos for the Perseid meteor shower and I got lucky the star trail composite photo turned out nice! Each frame of my pictures looked like the one below. This is 1 of 271 photos. Only 2 photos actually had meteors over about an hour and a half! I was unlucky I think.

After taking all of the photos and blending them together, they formed the star trails image below. To do this, I used Adobe Photoshop. To do this:

  1. Import all of your photos as different layers, there is a script in Photoshop to do this
  2. Select all of the layers and select “Lighten” as the blending method.

Tada! Star trails.

Bright star trail example
Dark star trail example

Other Planning Details

It might seem intense to plan but it isn’t so bad. If you plan on doing this often or other photo type things, Photopills is pretty great and helps a lot to get your timing accurate. For the one-off Stellarium or Google Sky can help you navigate what you are looking at etc… I’m personally terrible at this without help. You got this!

There will be a lot of planes/satellites… You can edit out the streaks in your image though!