PixInsight: Bi-Color Combination - Tutorial

Updated: Dec 23, 2021

Bi-Color imaging is often use on deep sky objects that are rich in two specific narrowband channels but lack one of the three. For example, the Pacman Nebula contains a lot of Hydrogen Alpha and Oxygen III gas, but lacks Sulfur II. Amateur astrophotographers sometimes decided to completely skip one of the three gases and use the limited time they have focused on the two richest ones.

Combining two master files from a monochrome Astrophotography camera into one color image can be tricky because, as you probably know, a color image is made of three channels (Red, Green and Blue).