Example image processing of an emission nebula in PixInsight and GIMP

Example of processing an image with emission nebula

Much of the important information in the sections on image processing was significantly influenced by Frank Sackenheim's Astrophotocast (https://www.youtube.com/hashtag/astrophotocast). Every beginner in the field of astrophotography is recommended to watch some of these very informative and interesting videos.

In this way, many thanks to Frank Sackenheim for his hard work in producing the videos.


For the image processing of astro images after stacking (see menu point 'Image processing' - 'Stacking and stretching of images') there are different approaches and programs. All of them have the goal to create an optically beautiful image. Every astrophotographer has a different approach and also different ideas how a successful image has to look like.

In this section, the workflow for processing emission nebula images taken with a color camera using PixInsight and GIMP will be presented.

To process an emission nebula, there are different ways, which also depend on whether and if so, which filters were used. If a Duo-Narrowband filter is used, the emission wavelengths must be extracted separately (see instruction 1) and then cropped and aligned with the original captures (see instruction 2). Depending on the filters used, there are the following possibilities: