Just a different way to process a globular cluster using Pixel Maths, to keep the core unsaturated and bring out some fainter stars from the outer edge.
1st image is a RGB using the masked stretch at 500 iterations and a preview around a background area containing no stars. The Masked Stretch keeps the core nice but doesn't reveal to many stars.
2nd image has a Screen Transfer Function stretch applied using the STF new instance added to the Histogram bottom bar and applied to the image.
This brings out all the fainter background stars but as you can see blows out the central core.
3rd image is a pixel maths blend of the two images using a formula from Gerald Wechselberger's Pixel Maths tutorial, meant for enhancing the contrast in galaxies. This has kept the core from the Masked Stretch image and the STF fainter stars. Gerald's excellent tutorials can be found here.
http://www.werbeagentur.org/oldwexi/PixInsight/PixInsight.html4th image is a sreenshot of Gerald's formula. I rename the STF image to just, s and apply the instance to the Masked Stretch image.
5th image the end product with a SCNR and an extracted luminance added. Even with no astro dark you can still produce an image. Now I need to find a tutorial on cleaning up my background skies :-)
6th image a new blend with the STF settings altered slightly so not as harsh a stretch. Then blended with the masked stretch. Thanks JulianR for the STF tip.
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