Combining James Webb or Hubble Legacy Archive images in PixInsight

I had watched a ton of tutorials on processing your own versions of HLA images before JWST started releasing data right off the bat (which is awesome btw) and lots of folks used Photoshop or if they did use PixInsight, it was 3 images combined directly in RGB or LRGB with PixelMath or LRGB combination.

That said, a lot of those compass images are created from 4,5,6, different images, using more colors than just straight RGB.

I could not for the life of me find someone that was putting out tutorials for creating more of those custom colors outside of Photoshop, which I am certainly not a pro at.

Some creative google-fu later, I found this post on the PixInsight forums.

The CombineImages script is an easy UI that has all the PixelMath color mapping built in so you don’t have to do it yourself (which I tried and it was terrible for experimentation). All you need to do is download it and install it just like any other PixInsight script.

For this script, have your images in Views (e.g. open in the workspace) and select them in the dropdown menus. Then on the right you select which color you prefer or change the RGB values for a custom one. DONE!

You can also add in any pre processing modifications as necessary.

Don’t forget, before you do this you need to do some alignment to those images, as they do not come star-aligned when you download them. Once you get your images all together, what I do is save the calibrated image in xisf (PixInsight Native) format and run the registration process (StarAlignment) on them. Pick one of the better images to use as your reference, just like you would your own data. The process will scale and register them relative to each other.

It’s important to keep in mind that it’s not a straight combination and you’re done kind of process. You may have to modify the strengths, blend, and do some post-processing to get the colors you want. Take a look at Judy Schmidt’s videos and you can see how she does it, which Nico Carver on NebulaPhotos.com did recently as well using Photoshop. It takes a bit of fiddling.

Again, for the visually inclined….video below.