How To: Star trails – Stacking with StarTrails.exe

How to take star trail photos like this:

The Camera Setup

Capturing star trails using the stacking method is much more demanding that the standard single exposure method. Mostly on your equipment, but also with the amount of work it takes to get the end result. It is usually worth it in the end though.

You should use the following settings as a guideline to get the best possible star trails:

• Shutter speed: 30 seconds
• You should take short 30 second exposures at regular intervals (with little gap as possible between the shots). It is advised that you a remote shutter release with the trigger locked on, and put the camera on “rapid fire” mode which will allow you to keep shooting without touching the camera for the duration of the shot.
• Aperture: f/5.6
• You will want to use an aperture that doesn’t let too much light in but not too little. Anywhere between f/5.6 and f/8 should be fine.
• ISO: 800
• Probably the most important difference here from the standard “keep the ISO as low as possible”. You will want to choose a relatively higher than normal ISO, this is because the short 30 second exposure still needs to be exposed properly. Adjust all your settings to make sure each and every shot in stack is correctly exposed. If you don’t do this important step, the end result will be dark, and not worth your time.
• Image quality: Large JPG
• This one is optional, but I prefer to shoot in “large jpeg” size when stacking. This makes the process a lot shorter. If you are a raw format shooter, you will find that on longer stacks (100+ shots) the process of batch exporting jpegs for the stacking software will be slow.

Of course, these settings will vary depending on the conditions, these guidelines are written assuming the sky is clear, and there is no haze which means there will be little light polution. If you require any further help on these settings, or if they aren’t working right for you leave a comment below and I will do my best to help you out.

The Software – StarTrails.exe

Before you go any further, if you haven’t already done so download StarTrails.exe now (link will open in new window).

• Step 1 – Load the files
• 
  To open the image selector, click on the button circled above.
• 
  Select the images you want to stack to make a star trail and then click open. This will load the images into the left-hand sidebar.
• Step 2 – Get stacking!
• Now you have loaded the files into StarTrails.exe, you should see something that resembles this:
  
• You are very nearly done, all that’s left is the click the “Star Trails” button, circled below:
  
  Once you’ve clicked this button, you might want to leave the computer alone to do its thing (it’s best to leave it alone, otherwise it’s trying to do a lot at once and will slow your stack down). Go and grap a cuppa, or go and take some more photos! Of course, it’s also quite interesting to watch the software stack, StarTrails.exe will update the image shown on screen as it adds each layer fromt he selected images for stacking.
• When the StarTrails.exe has finished its stacking, you will see the end result on screen. DO NOT close the software at this point and expect it to be saved somewhere, you must save the resulting image yourself!
  
• To save the image, click the button (circled below). When prompted, save the image to your location of choice.
  

That’s it! One thing to note is when you save the image from StarTrails.exe the EXIF data is stripped from the resulting image. This is a small annoyance if you upload your photos to sharing sites like flickr and like to share your settings. A possible workaround for this (if you are that bothered) is to take the EXIF data from one of the stack images, and then add it to the stacked image. A bit of a fiddle, but worth it if you need it.

If you need any further help, or clarification of the above please leave me a comment below and I’ll do my best to help you out.