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PixInsight: How to Add HA to RGB in Galaxies

Updated: Oct 19, 2023

Adding Hydrogen Alpha data to an RGB file will take your image to the next level, as you will be able to reveal HA regions that were before not visible! This is great for all types of objects where hydrogen alpha gas is present. For example, many galaxies have star-forming regions visible in the spiral arms, nebula almost always have hydrogen-alpha in them, and star clusters often lie against faint hydrogen-alpha background.

This tutorial will show you how to combine HA data with your RGB image in just a few simple steps using PixInsight. A video is also available for you to watch if you get confused at any point during this workflow.

Adding HA to RGB in PixInsight Tutorial

This tutorial is written specifically for galaxy data. It is a snippet from our full Galaxy Processing guide which processes M101 in-depth from start to finish. This tutorial is good whether you are using a color camera (with a filter for HA) or a monochrome camera. Go ahead and import your master files into PixInsight, and let's combine them into one!

Note: We've been using this method for some time now, which we originally found on Crazed Conceptions' YouTube channel Thank you for being the first to share this!


Pre-Requisites & Important Notes

To combine our HA with our RGB file, we will be going through three simple steps. Before we get started, it is important to understand the best time to do this combination. Before you start Step 1, we suggest having done the following to your data:

  • Your data is fully calibrated/aligned/stacked (and debayered if needed)

  • Masters opened in PixInsight

You should have either 2 masters (if you used a color camera, such as a color file and an HA/dual-band file depending on the filter used) or 4-5 masters (if you used a monochrome camera, such as R, G, B, HA or L, R, G, B, HA).

  • Dynamic Crop

Same crop applied to all masters

  • Background Extraction

Either DBE, ABE, GraXpert, or something similar

  • Detail Enhancements

  • Noise Reduction

PixInsight Stacking, Crop, Background Extraction, Detail Enhancements...