A common problem in narrowband images, especially using the SHO or Hubble Palette, is magenta-colored stars, or stars that have a magenta halo around them.
This article explains how to remove the magenta colored stars from your image. Your image can be in the linear or non-linear state to use this process.
Using SCNR With An Inverted Image
Use the following directions to reduce or eliminate magenta-colored stars:
1. Ensure you have an image having magenta-colored stars open on your PixInsight desktop
2. From the menu, select Image – Invert or press CTRL+I on your keyboard
3. Apply SCNR to the image (select Process – SCNR), using the default settings
4. From the menu, select Image – Invert or press CTRL+I on your keyboard
The magenta-colored stars or halos should be gone now. If you find that the effect is too strong, undo the application of SCNR (click Undo or press CTRL+Z twice) and reduce the Amount in step 3.
You can also use this process with a star mask so that you affect only the stars. Note though that a star mask may not capture the halos around your stars, so you may have to use the convolution process to enlarge the mask to include the halos.
Conclusion
In this article, you learned how to reduce or eliminate magenta-colored stars or magenta halos around stars using SCNR with an inverted RGB image.
More Articles In This Series
This article is part of a whole series of articles about processing images using PixInsight:
- For the narrowband processing workflow, click here for the index article for narrowband images.
