Getting better? But what about stars?

[rubecula]

I think I'm getting to grips with CCD and particularly narrowband imaging.  Below are my last couple of efforts.  The Cocoon Nebula is a HaLRGB image using Olly's recipe for adding the Ha, 15% to Luminance and 85% to the red channel.  The Elephant Trunk is a an SHO image.  In both case the processing has done nothing for the star colours.  Is there a way of protecting star colour during development or is the best way to remove them, stretch the image, and then put them back again.

If removing them is the best way I can see that there are a couple of apps to help with that (e.g. Straton and StarNet++) but how do you put them back?

Thanks

Thanks

[steppenwolf]

18 minutes ago, rubecula said:

If removing them is the best way I can see that there are a couple of apps to help with that (e.g. Straton and StarNet++) but how do you put them back?

You need to run either the Straton or StarNet++ processes twice with different settings so that you end up with a second image containing just the stars. If you are using PhotoShop, to add the stars back in again after you have processed the starless nebula, copy the stars onto the nebula as a separate layer and then change the blend mode to 'Screen'.

This can be a very effective way of processing as it gives you extra 'headroom' for stretching the nebulosity. However, there are also strategies for producing star masks to protect the stars in both PhotoShop and PixInsight.

[retret66]

I use pixinsight and I use colormask for each color channel, this will not touch your stars, you can adjust each color channel to whatever color you like and your stars remains the same..