My first attempt at photographing star trails was not a total loss.  I did not get the images I was hoping for but I did get some images that were acceptable and a good list of lessons learned for attempt number 2 (and 3 and 4 and 5…).Star Trail photograph in Phoenix AZ

First the basics, what is star trail photography?  A star trail photograph is one in which you capture the motion of the stars as the earth rotatesby using long exposure shots.  The trail of light you see in the image is the star at various points in the night sky as time passes and the earth moves.  In my image above I got the start of the concept.  But most star trail photos you see will have significantly more movement, i.e. longer trails, of the stars.  So for next time I have a few pointers.

1) The darker the sky the better.  That means you are going to need to head away from metropolitan areas and the light pollution they emit.  I also shot this three nights before the full moon which resulted in too much moon light to get optimal star trail images.  So drive out into the desert or country away from the city lights and consult a moon calendar before you go to make sure you have it as dark as possible.

2) No exceptions, you are going to need a tripod for this.  Hand holding will never work unless you have the steadiness of a rock for very long exposures.  But why risk it, take your tripod.

3) Focusing can be a bit tricky with photography in environments that are this dark.  If you can focus manually that is good.  Alternatively you can focus on something that is lit enough to see in the distance with auto focus then switch the camera to manual focus and aim the camera in the direction you plan to shoot.  Don’t do your star trail photography in the direction of the light source.  This will lock int he camera set auto focus and maintain it as long as you don’t change the focal length.

4) Camera settings: You will want to experiment here and find what works best for the setting you are in, but in general these are the settings that I found worked for me.

  • The lower the ISO the better to prevent noise (100 is best)
  • An f/stop in the range of 2.8 – 4.6 worked well for me
  • Set white balance to auto

5) Composition: Composition was a bit of an after thought my first time out photographing star trails.  But it shouldn’t be.  This is a matter of personal taste, but I think having something in addition to the night sky in your composition really enhances it.  That could be a building, trees (be careful of windy nights where a tree can blur in a long exposure) or a mountain or hill  the distance.  Make sure you pick something that is going to hold relatively still during your long exposures.

6) For the actual photographs you have two options.  Really long exposures using bulb mode or multiple long exposures.  I tried both and found that the bulb mode exposures did not work well for me.  I was getting too much noise and light interference.  If I had had a darker night that might not have been an issue.  But in this setting I found that the multiple long exposure method worked better. To use this method:

  • Set your shutter speed to 30 seconds.
  • Set the drive mode (as it is called on my Sony) to continuous.  Might be sports or action mode on some cameras.
  • Connect a remote shutter release cable and after you click it once lock it so that it stays held down.  This will allow the camera to continually take 30 second shots one right after the other.
  • The number of shots you will need depends on how long you want your star trails to be.  I would recommend at least 5 minutes, which is 10 shots.  But the longer the better.
  • DO NOT MOVE THE TRIPOD OR CAMERA.  This will ruin things for the next step.

7) Processing the images.  Once you have 10+ images you are going to need to combine them into one to make the final image.  There is a free star trail software program you can download that does a really good job of stacking your images and giving you a JPEG or TIFF file.

8) A few extras to bring along that can help.

  • A flashlight
  • A chair, you are going to want to be comfortable while you wait for these long shots.
  • Extra charged batteries.  Long exposures like these can really drain your batteries.  Be prepared.
  • A guide to the stars.  You might want to know what you are photographing.
  • A jacket.  It can get cold out in the middle of nowhere at night.
  • A friend.  It can also get lonely and scary out in the middle of no where at night.

Star trail photograph of the big dipper

So now I think I am ready to head out to the desert again and try my hand at star trail photography once more.  The next new moon is towards the end of the month according to my moon calendar and I am ready with what I learned this first time around.  Check back for attempt number two.


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