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How to Shoot Star Trails

The night sky can be a very interesting thing to photograph, provided that you have the patience to do so. I recently started photographing the night sky even though it has been cloudy for the most part here. A couple of people already asked me how it is done. So I decided to share what I know here. Please note that there is more than one way to do this.

What You Need

  • A camera with manual controls
  • Sturdy tripod
  • Shutter release cable
  • Preferably a fast wide lens
  • Clear sky
  • A lot of time

When and Where

It goes without saying that you need a clear night sky. It is better if it’s moonless night because it’s rather difficult to see stars with moonlight. It also helps a lot if you can move to an area where the light pollution is minimal. If you’re lucky, you might just be able to see the milky way (which is an awesome thing to photograph on its own).

Shooting

Set-up your camera on the tripod and compose it to your liking. Then switch to manual mode and turn your lens focus ring to infinity (maybe about a hair less than infinity). It’s always good to take a test shot first. Use the highest aperture of your lens (lowest f number), ISO 1600 or above if your camera is good with noise processing, 30 second exposures. It is important that you’re in the continuous mode. Once all the settings are dialed in, plug in your shutter release cable and lock it in the shoot position. Then it’s just a waiting game. If you don’t have a shutter release cable, a cheap solution is to use duct tape to press the camera shutter button. If it sounds stupid, but it works, it’s not stupid. The number of pictures you need depends on how long you want your trails to be. But generally you should shoot for at least more than 30 minutes to get reasonably sized trails. One important thing is that when we shoot landscapes we generally stop down the lens to f/8 or f/11 or so but when you shoot star trails, you need to have your lens wide open because you need to be able to collect as much light as possible. Even though the depth of field is going to be rather small, it is sufficient to contain your entire subject because the stars are so far away. If you have a big foreground, you may have to take several shots with the foreground focused so that you may combine them later in photoshop.

Post Processing

I use Adobe Bridge and Photoshop CS6 for almost all of my work. Import the pictures using Bridge, select them all and open them using Camera RAW. You can do all the global adjustments and sync the settings so that all of your pictures look uniform. When you’re done, do not click on “open images”. That would start opening all of your images in different tabs in Photoshop. Just click “Done” and it’ll save all of the changes you made. Once you’re back in Bridge, select all of your pictures again and go to Tools > Photoshop > Load Files into Photoshop Layers. This is going to take some time depending on how many images you have. All of your images will load into a single photoshop document. Select all of your layers except the bottom one and set the blending mode into “Lighten”.

Screenshot 2014-08-05 19.54

Setting the blending mode

You will immediately see the trails when you do this. If you have any unnecessary trails (air plane trails etc.), you can simply use a healing brush to remove them but you need to find the appropriate layer in order to do so. If they are visible, it might be a good idea to change the blending mode of the layers one by one instead of doing all of them at the same time because then you know exactly what layer contains what. This method is going to take a lot of time but like I mentioned before, you need to have the patience to shoot star trails. If your foreground is too light, you can use a layer mask to darken it. Once you’re happy with the result, you can flatten the image and go through your regular work flow. Noise reduction is almost always a must because you’re shooting at very high ISOs.

star trails

Canon Rebel T1i, EF-S 10-22mm f/3.5-5.6 USM, Adobe Bridge, Photoshop CS6, 98 Pictures (my OCD sensors are tingling), 10mm, 30 Seconds, f/3.5, ISO 1600, Taken at Pasikuda (Sri Lanka).

End Notes

It is awesome if you have a full frame DSLR with a very fast wide lens but I shot mine with an entry level crop sensor DSLR and a relatively slow lens. So it’s not impossible. Full frame bodies are better at noise processing than crop bodies. So you can crank up the ISO without worrying too much about noise. 

There are two ways to shoot star trails. One is taking a lot of pictures and combine them later like I described. The other method is to take one long exposure shot. If you want to do that, set your shutter speed to bulb mode and let it go for as long as you want to. But if you do take multiple shots, you basically have everything you need to make a time lapse later. Plus you might be able to capture some milky way shots while you’re at it. I prefer to take multiple shots.

milky way

Milky Way – 4 Pictures stacked, f/3.5, 30 Seconds, ISO 3200, 10mm

This is the first time lapse video I made and I have no experience what-so-ever when it comes to time lapse photography. I basically just used Lightroom to put the images together with no post processing. The reason why I put it here is to show you that it can be done. 

Hope you enjoyed this post and if you have any questions, I’d be happy to answer. Consider sharing this if you liked it. Thank you.