Author Topic: Dim galaxy and bright star(halo) - how to create the masks?  (Read 602 times)

Offline Herbert_W

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Hi,

The galaxy should become be a bit brighter and more colorful and the halo should be dimmer and less colorful.
In this image, it is not easy to mask the galaxy (without stars) respectivily the starhalo (only the halo, exclude stars and spikes).


How to create the masks to conform to PixInsight philosophy? Don't paint!



Any help is welcome!
Best regards!

Herbert, Austria
« Last Edit: 2017 November 14 06:58:20 by Herbert_W »

Offline RickS

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Re: Dim galaxy and bright star(halo) - how to create the masks?
« Reply #1 on: 2017 November 14 07:24:18 »
I only had a few minutes but here's a quick mask for the halo.  Created with: ColourMask (Blue), Convolution, HT clip/stretch, Convolution, PixelMath "$T-CIEL(m109_info)*0.7"  Apply to image and use CurvesTransformation to reduce blue and green.

Cheers,
Rick.


Offline RickS

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Re: Dim galaxy and bright star(halo) - how to create the masks?
« Reply #2 on: 2017 November 14 07:46:26 »
I had a few more mins...

Processing: extract CIE L, MLT remove layers 1-5, HT clip/stretch, PixelMath "$T-CIEL(m109_info)*0.5", HT stretch and then a possibly controversial final step: draw a preview around the galaxy and use the SubstituteWithPreview script to copy it into a black image (created with PixelMath "0")

Cheers,
Rick.

Offline Herbert_W

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Re: Dim galaxy and bright star(halo) - how to create the masks?
« Reply #3 on: 2017 November 14 11:07:21 »
Hi Rick!

Thank you very much for your effort to show me your steps to create the masks.

Colormask - of course! It's quick and easy to create a mask for a certain color.
I like also your idea to multiply the subtracted light component with a coefficient to refine the mask.

Some improvements to my workflow - thanks!

Best regards!
Herbert, Austria


Offline Alejandro Tombolini

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Re: Dim galaxy and bright star(halo) - how to create the masks?
« Reply #4 on: 2017 December 03 00:25:56 »
Hi Ricks, excellent approach!, I will start using it with this kind of halos.

Saludos, Alejandro.