Russell Croman Astrophotography  




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StarXTerminator is a tool to remove stars from astronomical photographs that works in Photoshop and PixInsight. This allows separate processing of stars and background objects, or simply leaving out the stars altogether.

StarXTerminator uses an advanced convolutional neural network with a unique architecture suited to this task. This network has been extensively trained on photographs from both refractors and reflectors, so small stars, big stars, huge stars, and even diffraction spikes are recognized and removed, with minimal impact to non-stellar features. StarXTerminator can even remove stars with dark halos around them from deconvolution or sharpening. An accurate feathering algorithm eliminates the tiling artifacts produced by other solutions.

The end result is a very smooth elimination of stars, with minimal residual artifacts and excellent color matching.

StarXTerminator adopts a "universal licensing" scheme: a permanent license for any version (Windows/Mac/Linux, Photoshop/PixInsight) will work on any other version.

Recommended Usage

  • Use StarXTerminator as early in your processing flow as possible. Though it has been trained to remove sharpened stars and stars with dark halos, better results are possible on lightly processed photographs.
  • Before running the filter, duplicate the target layer. This allows easy evaluation of the results as well as access to the original photograph in case any non-stellar features were removed.
  • If you plan to use NoiseXTerminator on an image in addition to StarXTerminator, apply StarXTerminator first. NoiseXTerminator can do a good job of cleaning up minor imperfections in the star removal process, while using StarXTerminator on a very low-noise image can leave these artifacts behind.
  • If you want to create a layer with just the stars so they can be processed separately and added back in later, do the following:
    • Duplicate the target layer twice
    • Process the top-most layer with StarXTerminator
    • Duplicate this layer, then make it invisible
    • Select the first starless layer and set its blending mode to "Subtract"
    • Merge this layer with the one below – this is now the layer with just the stars
    • Move this layer to the top and set its blending mode to "Linear Dodge (add)"
    • Make the remaining starless layer visible again
    • You should now have three layers: the original photograph, the starless photograph, and the stars themselves

System Requirements

Please see current known issues and planned improvements on the support page linked above.

StarXTerminator requires a computer with a modern CPU having instructions required to run neural networks. Older CPUs lacking FMA, AVX, and SSE instructions are not supported. Request a trial before purchasing to make sure it will work on your machine.

  • MacOS
    • Version 10.15 (Catalina) or later
    • Photoshop CC or PixInsight 1.8.8-9 or later
    • GPU/Neural Engine recommended for fast performance, but not required. Not all GPUs are supported. StarXTerminator will automatically use the CPU if the GPU is not supported.
    • Apple silicon (e.g., M1, M1X) supported natively
  • Windows
    • Windows version 10 or later
    • Modern CPU capable of running neural networks (AVX, SSE instruction set extensions)
    • PixInsight 1.8.8-9 or later, or
    • Photoshop CS4 or later (64-bit only)
  • Linux
    • Ubuntu 18.04 or later, or equivalent (glibc 2.27 or later required)
    • PixInsight 1.8.8-9 or later

Photoshop Plug-in Version History

Version Date Comments
1.3 Coming soon! Improved handling of the edges of images.
1.2.2 30 Sep 2021 Update for Windows version only: eliminates the need to move the three Microsoft DLL files to Photoshop's or Affinity Photo's application directory. These files can now be placed alongside of the plugin file itself (StarXTerminator.8bf).
1.2.1 27 Sep 2021 Update for Windows version only: reverts to running only on the CPU. GPU selection was found to be unreliable. This will be addressed in a future update.
1.2 26 Sep 2021 Supports processing of 8- and 16-bit RGB and grayscale photos. Windows version selects GPU if available. Removed batch size adjustment and calibration (unnecessary). Fixed compatibility with Affinity Photo for Mac.
1.1 18 Sep 2021 Adds native greyscale image processing. Adds AI download for Mac version, and download progress indicators for Windows and Mac versions.
1.0 12 Sep 2021 Initial release

PixInsight Module Version History

Version Date Comments
1.3.1 12 Jul 2022 Added batch processing function to save starless and stars images generated from a collection of input images.
1.2.0 8 Jan 2022 Fixes an issue that prevented the "stars" and "linear" parameters from working correctly in scripts and ImageContainers. The stars-only image now inherits the FITS parameters and astrometric solution of the original image. MacOS: fixed a memory leak.
1.1.0 8 Nov 2021 Necessary for compatibility with AI version 6. Uses PixInsight's update repository system for installation. AI files are now installed as part of this process.
1.0.0 8 Oct 2021 Initial release

AI Version History

Version Date Comments
10 18 Apr 2022 Corrects a malfunction in the noise matching module that could cause black or white squares around the edges of uncropped images or in clipped regions of images. Same core neural network and training as AI8.
9 9 Apr 2022 Corrects a malfunction in the noise matching module that could cause black or white squares around the edges of uncropped images. Same core neural network and training as AI8.
8 18 Mar 2022 Re-trained from scratch for greater precision in removing stars and retaining non-stellar details. Training data set further expanded to include tough cases such as bright stars, crowded star fields, and especially galaxies and galaxy clusters. Particular attention given to retaining galaxy disk details such as H-II regions. Also includes an improved statistical noise matching engine that matches the noise statistics of surrounding areas when removing large stars, making these areas blend into the rest of the image.
7 16 Dec 2021 Revamped neural network architecture giving greater accuracy of star removal and better retention of non-stellar structures. Trained on an expanded data set that includes more galaxy images, resulting in better retention of galaxy cores and non-stellar details in spiral arms. AI7 retains much more detail around stars than AI5, largely correcting the overly-smooth areas of that version.
6 8 Nov 2021 Only available for PixInsight version at this time. Implements matching of noise statistics for replaced pixels, resulting in a more natural appearance and elimination of the "smooth" areas around stars seen in earlier AI versions.
5 26 Sep 2021 Improved handling of monochome narrowband and noisy nebula photos.
3 18 Sep 2021 Much better handling of wide-field (short focal length) galaxy images. Better handling of crowded fields of small stars from short focal length instruments. Better avoidance of small non-stellar features (e.g., small patches of nebulosity and background galaxies).
2 12 Sep 2021 Initial release

Is this StarNet++?

In case you are wondering if StarXTerminator is just the popular StarNet++ repackaged as a Photoshop plug-in or PixInsight module, it is most definitely not. The neural network architecture, the training data set, the training method, and the supporting algorithms for tiling and batch processing are completely different and unique.