How to Use StarStaX to Create Stunning Stacked Star Trail Images

Have you ever gazed up at the night sky and wondered how photographers create those breathtaking, smooth arcs of star trails, you’re not alone. One of the most popular and easy-to-use programs for making these beautiful images is StarStaX. Whether you're a beginner or an experienced photographer, StarStaX can help you create star trail images quickly and efficiently.

In this guide, we'll go over how to use StarStaX to create star trail images as well as explain each key feature in the blending modes.

What Is StarStaX?

StarStaX is a free (yes, you read correctly, FREE), cross-platform software designed for stacking multiple images together. It's commonly used to create star trails by blending a sequence of night sky photos. The software is powerful yet simple, enabling you to combine dozens or even hundreds of photos into one seamless final image.

Step 1: Preparing Your Photos

Before using StarStaX, you need to capture a series of long-exposure shots of the night sky. These photos will then be stacked together to form a star trail image. A good starting point for each individual image is an exposure of around 15-25 seconds per frame, and you’ll want to shoot continuously for at least 1-2 hours to capture significant star movement. You can check out my Beginners Guide to Timelapse Photography: Tips and Essential Gear (katgphotography.com) for more information on how to capture a timelapse. Once you’ve taken your photos, you'll need to edit them (I like to use LRTimelapse and Lightroom to edit all my timelapses) and export the edited photo as a jpeg.

Step 2: Opening StarStaX

When you launch StarStaX, (you can download the free program here), you’ll see a simple interface that allows you to load your photos and adjust the stacking settings.

• File Input: On the left side of the window, click on the "Add Files" button or drag-and-drop your star photos into the left "Drop Images Here" area. Make sure to select all the edited photos in that folder before adding.

  

  
  

  

  
  

• Dark Frames: If you've taken dark frames (photos with the lens cap on to capture sensor noise), you can add them using the “Add Dark Frames” button. These will help remove noise from the final image.

  
  

Step 3: Choosing a Blending Mode

One of the key features of StarStaX is its blending modes. These control how your images are combined. Each mode has its own purpose depending on the effect you're trying to achieve. I explain each mode in more detail below:

1. Gap Filling Mode

This is the default mode for star trail photography. It works by filling in some gaps between stars in consecutive images and is especially useful when there are minor breaks between exposures (like delays between shots in your camera’s intervalometer). This mode creates smooth, continuous star trails. Once your star trail image is finished processing, you'll want to adjust the threshold so that the green is only highlighting the star trails. From there you can change the amount of brightness to less or more to get the desired look you are going for.

Green Threshold on Star Trial

2. Lighten Blending Mode

In this mode, StarStaX takes the brightest pixels from each photo and combines them into the final image. This is perfect for star trails because the stars (which are bright points) will be highlighted and blended together across all frames. It ensures that only the brightest parts of each frame contribute to the final image, creating crisp, clean trails.

3. Average Blending Mode

This mode calculates the average pixel value for all input images. It’s less commonly used for star trails (I wouldn't recommend using it but it's there as an option) but is useful for creating composite images where you want to retain details without too much brightness or if you're looking for a less intense trail effect.

4. Additive Blending Mode

Additive blending sums the pixel values of all images, creating an extremely bright final result. This is great if you want to make the stars in your trails really stand out but be careful—overuse can lead to overly bright or blown-out areas in your image. I tried to create an example for you, but the image was so bright at the end, it didn't look great.

5. Darken Blending Mode

Darken blending takes the darkest pixel from each image. It’s not commonly used for star trails but can be helpful in removing unwanted bright spots, such as aircraft lights, from the final image.

6. Subtract Blending Mode

This mode subtracts pixel values from each image. It’s rarely used for star trails but can be useful for specific artistic effects or to reduce certain bright elements in an image sequence.

7. Comet Mode

Comet mode is a feature that helps create a "comet-like" effect in star trail photography. Instead of creating smooth, continuous trails for each star, the program gradually fades out the stars' trails as they progress across the image. This gives the appearance of a "comet" tail: the trail starts bright at the beginning and fades toward the end. You can choose how long or short you want the tails to be by adjusting the bar underneath the comet mode.

Step 4: Stacking Your Images

Now that you understand what each feature does, we can get to the fun part!

Choose your blending mode (typically "Gap Filling" or "Lighten" for star trails), you're ready to stack the images:

1. Load all of your individual star photos into the program by clicking 'File-open images' or by clicking on the first icon with a star and folder circled below.

   

2. If you have dark frames, load them as well. Be sure to tick the box that says, 'Subtract Dark Images'.

3. Click on the 'Start Processing' button or you can go to 'Edit- Start Processing'.

   

StarStaX will now begin to process your images and stack them together according to your selected blending mode. Depending on the number of images, this can take anywhere from a few seconds to several minutes. There will be a green bar on the bottom left corner of the program, to show you how far it is processing.

Step 5: Saving Your Final Image

Once the processing is complete, StarStaX will display your final star trail image in the main window. At this point, you can make final adjustments or simply save the image.

• Click on the "Save As" button to export your star trail image in the format of your choice (JPEG, PNG, TIFF, etc.).

  

  
  

• Pro Tip- If you are still going to do more post-processing after the fact in Lightroom or Photoshop, make sure to add .tiff at the end of the name of the file to create a tiff image and not a jpeg (it defaults to jpeg).

  

  
  

Step 6: Optional: Create a Star Trail Timelapse

One additional cool feature of StarStaX is the ability to create a timelapse video showing the stars as they move across the sky. Before stacking your images, you can save each step as a separate file and then compile them into a timelapse using video editing software. Be sure to check the "save after each step" box, rename your file and select the output folder before clicking start process.

Tips for Better Star Trails:

1. Minimize gaps between exposures: To create the smoothest trails, aim to minimize or eliminate gaps between your exposures by using an intervalometer that shoots continuously.

2. Use dark frames: Adding dark frames can significantly reduce noise, especially if you're shooting in warm weather or using long exposures.

3. Post-processing: After creating your star trail image in StarStaX, you can further enhance it by adjusting the contrast, brightness, and color balance in programs like Photoshop or Lightroom.

4. Foreground elements: If you're shooting with trees, mountains, or other foreground elements, consider creating a separate exposure for the foreground and blending it with your star trails in post-processing to reduce noise and enhance detail.

   
   

Conclusion

StarStaX is an incredibly powerful tool for creating mesmerizing star trail images. With its simple interface and versatile blending modes, anyone can create stunning night sky photos. By understanding the blending modes and how to prepare your photos, you'll be well on your way to mastering star trails. So, get out there, shoot the stars, and let StarStaX do the rest!