How can I mask the core of a galaxy but not the stars?

[siovene]

Hi,
I'm very new to PixInsight and I'm loving it! I shoot with at 500mm focal length, and during this time of the year, galaxies are a tasty target.

Given the short focal, galaxy cores will be as small as some of the bright stars in the field. Sometimes I want a mask to operate only on the core of the galaxy, still protecting the stars. Do you know if there's a way do this?

Thanks!

[Alejandro Tombolini]

Hola Siovene,

Asumiendo que tenés una foto similar los siguientes seteos podrían funcionar.


Hi Siovene,

Considering that you have a similar picture, the following settings could work.


Alejandro.

[siovene]

Thanks Alejandro, but that just gave me the stars. I want to work on the galaxy core only, so I would like a mask where the galaxy core is white, and everything else is back.

[Alejandro Tombolini]

Hola Siovene,

Entiendo, pero no se como hacer esa máscara.
Otra posibilidad sería que uses la máscara de estrellas y trabajes sobre el nucleo con HDRWavelets.

 

Hi Siovene,

I understand but I do not know how to make that mask.
Another possibility is to use that mask for stars and work in the core with HDRWavelets.

Saludos. Alejandro.

[Juan Conejero]

Hi Iovene,

Welcome to PixInsight Forum.

A mask built algorithmically (that is, without arbitrary manual intervention) won't allow you to do that, in general. Nevertheless, in order to answer your question I need to ask you: why do you need to isolate the core with a mask in that way?

[caliu]

It's easy, you can to extract Luminance, and binarize, next use Painting/CloneStamp, easy.....

[mmirot]

Hi Iovene,

Welcome to PixInsight Forum.

A mask built algorithmically (that is, without arbitrary manual intervention) won't allow you to do that, in general. Nevertheless, in order to answer your question I need to ask you: why do you need to isolate the core with a mask in that way?

How about masking a Star Mask and combining it with a second mask containing the inverse of core in Pixel Math?

Max