I’ve been practicing to refine my technique of combining three greyscale images filtered in blue, green, and red. The basic idea is described in this recent blog post. There are a lot of things that can be varied. Sometimes the composite color image is too red, too blue, too green, too yellow…you get the picture.
I am now using FITS Liberator software to adjust the original FITS images and save them as TIFF images. Next, I use Photoshop CS5 to combine them into the three channels needed by an RGB image. Here are the two most recent images. Click each to embiggen for details.
NGC stands for New General Catalogue of Nebulae and Clusters of Stars. It includes all types of deep space objects and is not confined to galaxies. It was compiled in 1888 by John Louis Emil Dreyer and has been revised and modernized many times. The full NGC list is linked here.