Creating starless images is useful for a variety of reasons including making it possible to process just the subject of an image independently from the stars in the image.

While there are several techniques available to you for remove stars from your images, the technique I demonstrate in this tutorial is a single step and provides very good results.

StarNet++ is a free, downloadable Windows 64-bit application that has just one purpose –  to remove the stars from your images.

The Results

This is the original image of IC1795 with stars:

This is IC1795 with the stars removed by StarNet++:

It took about 45 seconds for StarNet++ to remove the stars in this image. There are still four large stars left in this image, however, you can easily remove them using tools like the Spot Healing tool or other content-aware tools in Photoshop.

A Note About StarNet++

StarNet++ is a neural network, which means it uses artificial intelligence to detect and remove the stars in your images. It also means that this software was written and is designed to run on systems made after 2011 only. The application relies on certain instructions being available on your CPU and CPUs made before 2011 do not support this instruction.

In addition, StarNet++ only works with 64-bit Windows.

StarNet++ is a commandline utility, so you need to be comfortable typing commands and using the command prompt window.

Acquiring and Installing StarNet++

You can download StarNet++ from here: https://www.starnetastro.com/ SoureForge here: https://sourceforge.net/projects/starnet/

Navigate to the downloads page and download the package appropriate for your needs.

Once the download is complete, extract the contents of the ZIP file somewhere convenient on your system; review the ReadMe.txt file in the ZIP file.

Testing Compatibility of StarNet++

Ensure your system is compatible with StarNet++ by running a test that comes with the files you just installed.

Use Windows Explorer to navigate to the location you unzipped StarNet++ and locate the file called run_rgb_starnet.bat.

Double-click that file and observe the output. If you see a message similar to ‘application could not start properly’, it indicates that your system is not compatible with StarNet++.

Otherwise, StarNet++ will convert the test input file into an output without stars. You can see the result by opening rgb_test5.tif once the process completes.

Using StarNet++ With Your Own Images

StarNet++ operates on TIF images in 16-bit color mode. This means that you might need to change the mode on your images in Photoshop or GIMP before saving them as TIFF format.

In Photoshop, open your image that contains stars, and select Image – Mode. Ensure that RGB Color is selected, along with 16Bits/Channel.

Once you have made those selections, save your file as a TIFF.

Copy your TIFF to the folder where you saved StarNet++.

Note that the following directions are for the commandline interface (CLI) of StarNet++

Open a command prompt window and change to the folder where StarNet++ is installed:

Type the following command

rgb_starnet++ <input_image> <output_image>

Replace <input_image> with the name of your image and replace <output_image> with the name of the image you want to use for the starless image.  

Once you press Enter, StarNet++ performs the conversion and finishes.

You’ll be able to open your resulting TIFF in Photoshop or whatever imaging software you usually use.

Conclusion

You learned about star removal from your images, learned about StarNet++, how to acquire it, and how to install and use it. This is an effective and fast way to remove stars from your images.