Separating selection from action that works on the whole image

[jon40869]

Hi everyone, my first post on here, still finding my feet with PS.

I have the Noel Carboni Astronomy Tools Action Set, I am trying to remove the purple halos around stars in an image of the Large Magellanic Cloud, however when I use the tool it removes a lot of the colour in the nebulosity of the (dwarf) galaxy (I also used Defringe in Lightroom which had the same effect).

I have tried to select the galaxy with the lasso tool and invert the selection and then run the action, however it applies the action to everything still.

I wonder is there a simple way to separate out the galaxy, run the action and then put the galaxy back in? Can it be done using a mask and then blended back in? If so I'm not quite sure how to do this.

Thanks in advance.

[JJMack · Accepted solution]

If its a layered document you can add a new empty layer on top and stamp visible layers into it.  Color range black and invert the selection to select what is not black empty space. You will still have the purple halos in the selection.   The selection should be better then a lasso tools selection

[jon40869]

Thank you for your response JJMack