Photographing Star Trails.

Ok gang, I’ve finally found some time to sit down and gather my thoughts.  It’s been really hectic here since the New Year and I’ve been a bit unfocussed when it comes to photography in general.
I thought the next natural progression in our learning curve would be to shoot some star trails.  This is something that I’ve never done myself so I’ll be learning alongside everyone on this one.
Even though I’ve never photographed star trails, I feel as though I can give you some tips to help make your experience a more enjoyable one.
Things that we have to remember even before we head out to shoot at night and in the elements, is to PLAN!! 
DO NOT go out without a plan in mind.  This is the quickest way to failure and to a potentially dangerous situation.   First and foremost is your safety.

If you are in North America you can first visit the Dark Sky Charts site  This site is a forecast (not always 100% accurate, but close).  This will probably give you the best opportunity for success when it comes to having stars to shoot.

Pre scout a location and set up when it’s still light enough to see.  Doing this is both good for setting up a foreground interest, and for your safety.  I’d hate for anyone to injure themselves by stepping into a rut or hole that they can’t see due to the darkness.

Consider the weather.   It might even be a good idea to pack a lawn chair and few blankets to aid in keeping warm.  I’ve always found that the more layers of clothing that you are wearing, the warmer you will be.  The other thing I’ve noted over the years is that it’s a lot easier to take off clothing because you are too warm, than it is to stay warm with too little clothing!!!

Now, you have a location in mind that is away from the bright lights of the city, you have yourself some nice warm clothes and possibly blankets, some hot coffee (or hot chocolate) you are ready to begin.

There are a few other things that I didn’t mention that you will obviously need, a good tripod, your camera (capable of shooting in either bulb mode with a cable release or for 30 seconds or so), fresh batteries (or a few sets) and an empty, large memory card to store the individual shots that we will put together.

I should mention a bit more about location.  You can’t really drive far enough away from city lights, over long exposures with the ISO cranked up on your camera you’d be surprised at how much light will show up.  You can shoot star trails with light pollution, but more stars will show up, and the background sky will look far better the further away from light pollution you can get.

Ok, now that you’ve found a nice dark location you can set up your camera and tripod.  I’d suggest focusing on your foreground interest while you still have some light, it gets quite difficult to focus a camera in the dark.  Make sure once you’ve focused the camera on the foreground subject that you put the camera in Manual Focus mode or it could possibly (depending on your settings) try to focus if you choose to do multiple exposures and stack them.

Once you are ready to go and the skies have darkened, try a test shot or two.  The reason for doing this is twofold, one, you can make sure the shot looks like you want it too, and secondly, you can adjust the white balance to suit your particular preference (I like the tungsten setting as it gives the sky a bluish look.

Again this next portion is up to you.  You can choose to either use a single shot or stack multiple shots.  Single shots will have shorter star trails and stacking will get you that long star trail look.

If you are using a single shot, I wouldn’t suggest using a high ISO as you will get more noise in the shot.  It’s a bit of a trade off because you’ll also get fewer stars in your shot.  This is where you will have to experiment to see what works best for you and your camera.  Another thing to remember when using a single shot is that the longer your focal length, the longer the star trails will be in any given exposure.

If you’re choosing to stack I’d suggest using a free program called *StarStaX*, it works with Mac OSX, Windows, and Linux so everyone should be good to go with stacking.  Here is where you can get the program

When stacking I’d personally resist the urge to use your lens wide open.  Most lenses get “Soft” and are more prone to chromatic aberration when wide open, set it one or two stops away from wide open, you’ll still get some good results.  For stacking you can also bump the ISO up a bit, but make sure to not make the image noisy.  For example, my old entry level DSLR had horrible noise levels at anything higher than 400 ISO, my new camera can go up to 800-1600 before the noise is too much for my liking.

To make it easy I’d shoot in JPEG instead of RAW.  That will keep the files smaller which will waste less time writing to the card, and allow for more shots on your memory card.  Remember you want to have the star trails appear to be continuous.  *Turn off your high ISO and Long exposure noise reduction in the camera, it will take too long to write the image* (more on this later)

If you have the use of a laptop and power source you can even control your DSLR from the laptop.  There are programs for most DSLRs that will allow you to shoot continuously and store the shots on your computer.  Some programs allow you to shoot longer than 30 seconds while others don’t.  There are both free and paid versions of these types of programs.

  • So again, the keys for stacking are long exposures (30+ seconds)
  • few stops away from a wide open aperture
  • Higher ISO
  • 30+ second exposures one right after the other.
  • Use a computer, cable release, or the settings on your camera (if it allows) to take continuous shots.

Take a couple practice shots to see if anything is too bright (foreground interest) for your liking.  If your foreground interest is going to be too dark you can use a flashlight to “paint” the foreground interest in your first couple shots.  This way it won’t be just a silhouette in your image.  (you might want to practice doing this before attempting during a star trail shot) also do it in the beginning of the sequence and another at the very end.  If you mess up you can exclude them and it won’t leave a gap in your star trails.

The last thing to mention is after you’ve taken all of your images, put the lens cap back on and take a few shots of the same length with the cap on.  This is called taking a dark frame.  The reason you do this is to help eliminate noise in the shots.  The key to dark frames is to take them at the same settings and temperature that the images were taken at.  The reason for telling you this is that some of the programs out there for stacking allow you to use dark frames to help reduce noise.  I’ll explain this better in the next little while.

If there are any questions you can post them here or in my blog.



  1. Having done many star trails myself, I can offer a few points of advice, though Daryl hit just about every major point pretty well:

    1) Though the genre of photo is astronomical, the terrestrial context is the most important aspect of the photo-you will quickly tire of taking the same shot of stars over and over again (though it is good to do this at the beginning for practice). Just like in regular landscape photography, though, foreground is key.

    2) DARK SKIES!!! I cannot stress this enough. If you live in a city, try to make time to get out (preferably far out). I'll eventually write up something for this series on Signal to Noise and sky brightness, but the long and short of it is: the darker your sky is, the lower ISO you can use, and the better your results will be.

    3) Become familiar with setting your camera and lens to focus at infinity (for stars) in the daylight. Know it well enough to do in the pitch black. I can't tell you how many nice photos have been ruined by being slightly out of focus-many times, they look fine on the camera's built in screen, but when I get them home to a computer, they're hopeless.

    4) You DO need to set your ISO higher than you normally would in daylight-this is unavoidable. However, try to resist this as much as possible-find out the lowest possible ISO you can get away with and try to work with that. The key in doing stars is low noise. Don't worry if you're setting your ISO above 1000, though-some situations demand it. Experiment, and you'll find the best compromise!

    Can't wait to see the class's results here! I'll be going out to Mauna Kea next week, so expect some stuff from me then.

  2. Hi Darryl, I thought about contributing to your blog with my photo if you like.


    Where: Albufeira, Algarve in southern Portugal is famous for it's great weather and beautiful beaches and cliffs.

    How: This photo is the result of 76 30sec exposures, blended together using the free software StarTrails (, and a 2 minute exposure for the foreground. There was a very bright moon that contributed for a good foreground exposure.

    As always, critiques and advices are welcome!

    Take care,


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