Back to forums

Before and after NGC7000

Processing Deep Sky NGC7000 NGC Objects
3 replies•349 views
Daniel Arenas avatar
Daniel Arenas avatar
Hello everyone,

I just want to share with you a reprocessing of NGC7000 and how it has changed. That was my very first processing in July 2022:



Now I stacked again the files with the latest version of WBPP 2.4.5, used SPCC and GHS, and It looks like different, as I have more details in the structure.



But I have some halos, is there any recommendation to get them out? It doesn't disturb too much to me, but I don't know if there's any easy way to remove them. I've tried the CloneStamp process in PixInsight, but I didn't have good results.

Clear skies dudes!
Helpful Engaging
Emmanuel Valin avatar
Emmanuel Valin avatar
Hi Daniel,
I would recommend to separate stars from the rest with Starnetv2, to process stars and nebulosity separately and to reincorporate stars only at the very end with PixelMath.
CS,
Emmanuel
Helpful Concise
Daniel Arenas avatar
Daniel Arenas avatar
Hi Daniel,
I would recommend to separate stars from the rest with Starnetv2, to process stars and nebulosity separately and to reincorporate stars only at the very end with PixelMath.
CS,
Emmanuel

Hi Emmanuel,

So, instead of applying GHS over all the image and then separate nebula and doing again fine processing with GHS you propose to separate at the beginning and then doing a non-lineal stretch with GHS separately one for stars and the other for nebulosity. Is that?

In that new processing, I did a GHS global to stretch the whole image and then separate the nebula and the stars to continue.

Now, as I stack with WBPP in R, G and B channel and then ask the script to combine them, I will test to process each channel separately (basically to do DBE) and try to eliminate halos, cause for example in R channel they don't appear. Maybe in G channel, I've to investigate.

Thanks for your comment ;)
Olly Barrett avatar
Olly Barrett avatar
Hi Daniel…
Regarding halos, the best way I’ve found is to do star removal after pre-processing and combining channels… I use StarXTerminator and it normally removes just the star and leaves the halo behind. I then take the starless image into Photoshop and use a combination of clone stamp and healing brush to carefully remove the halo and match the background. If you only have Pixinsight then use clone stamp…

To add stars back (after all other editing) I use the stars image as a mask in Pixinsight… 
Lets say the stars only image is called ‘RGB_stars’, then after using it as a mask use the following Pixelmath formula with ‘replace image’ selected…

$T+RGB_stars 

Then drag the triangle onto the starless image, this will add the stars back through their own mask and give you few to no dark rings around them.

Hope that helps answer your question 👍🏻

The big star at the bottom left of my NGC7000 image below is the same one you have the halo around, it had a large halo removed by the method I described.
I know this is narrowband but the technique works well for RGB too…

Clear Skies and Smaller Halos‼️
Olly
Helpful Engaging Supportive