Bloated haze around stars?

[Astroblagger]

Hello im looking for some help, when processing my mono images my stars get really bloated and large halos around them as seen right and upper right, when i stretch them as seen in this image of M3, i do a star selection and expand/feather as to not affect the stars when processing but the area around the stars lighten as i stretch the image? how can i stop this happening? Any help or advice appreciated.

[Tinker1947]

It might be a IR filter is required,,,,,

[Astroblagger]

I use an astronomic LRGB filters?

[ollypenrice]

Looks as if you've used a star mask when stretching this image? If so the star masks need to be bigger.

If not, you're getting strange effects with a tight inner star, then a quite separate outer halo.

Could you run through your workflow?

Olly

[Astroblagger]

I open the lum stack, select stars, expand then feather, then inverse to only stretch the faint detail minus the stars, then process as normal, seems to brighten the area around my selection, even though its been isolated with marching ants??

[Tinker1947]

Doh,,,i miss read the thread, thought it was bloated stars, not bloated after processing.....

[ollypenrice]

I open the lum stack, select stars, expand then feather, then inverse to only stretch the faint detail minus the stars, then process as normal, seems to brighten the area around my selection, even though its been isolated with marching ants??

Ah, right. I thought it would be something like this. It just doesn't work. I know it's a tempting idea and I've tried it myself but I always got the effect that you did here.

A better way to mask stars in Ps is to make a copy layer and a layer mask. Paste the image onto the layer mask, select and expand the stars a little, blur them, then black clip away all the nebulosity. Turn the mask into a negative (Ctrl I) and then stretch the top layer image. You can't stretch hard under a star layer mask like this. Nor can you expect the mask to work on many iterations of stretching. But if you even get a small part of the stretch done under the mask you'll still get slightly smaller stars.

Olly

[Astroblagger]

Cheers olly will give this a go then. Many thanks.