Last Updated on December 10, 2021 by Juan Ignacio Jimenez

We start with the image (this image I’ve applied the method with which the result will be exaggerated)

clone 2 times (image A and B)

Image B apply ATW 6 layers and delete layer R

With pixelmath Image A – image B

And then, Range selection in image A, Lower Limit use the slider until it occupies more or less the area of the nebula. In smoothness = 8. click on OK, and that creates a new image which we’ll call Nebula. Important: Do not close the window Range Selection

Click in Image A. and re-use the Selection Range slider to the left to cover more background, but what would cover areas without any cloudiness and apply and rename Background. Now we have 2 image.., Nebula and background

Now Pixelmath, Background – Nebula and apply in Background image. it remains part of the nebula called Background image leaving only the background

Now.. deconvolution to 40 StdDev

Apply background mask in original image, as you see, the mask protect only nebula and real background (without clouds)

And now…, histogram transformation, move the slider to the left of the middle to get the background signal…. you can see the difference in the preview. This image I’ve applied the method with which the result will be exaggerated