gimp + "stretched view" + "cloning"

[TiffsAndAstro]

been some time since i've used any processing software and gimp is free. i can basically open and save stuff, but i'd like to try, er cloning/smoothing out some parts of the starless image outputted from starnet, from a sprial galaxy image. mainly just to see if i can then stretch it further before bringing out too much noise.

im gonna watch the link below but just wondered where the 'stretch view' (like i use in siril) is located or called? i can't google it if i don't know the official term. Also i assume gimp has a basic clone type tool for me to play about with?

 

Edited April 25 by TiffsAndAstro

[ollypenrice]

What I would do (what I do do!) is make a basic stretch from linear till my background sky is just a little darker than I'd like it in the end. I de-star that.

I take the starless and open Curves (This is Ps but I guess GIMP is the same). I place a fixing point on the curve at the brightest point in the background sky. I place a second fixing point below that. If I now lift this curve from just above the two fixing points I'm stretching only the galaxy, which is what I want to do.

Once I've done this, I can do the opposite for the background sky. Again in Curves, I pick the brightest point in the background sky and put in a fixing point. I'll then put a series of fixing points in above that, this time, so all the galaxy stretching will be unaffected. Now I can pick a point below the brightest background fixing point and lift it, so reducing background sky noise. Don't eliminate background noise, it will look oily and false.

Olly

[TiffsAndAstro]

1 hour ago, ollypenrice said:

What I would do (what I do do!) is make a basic stretch from linear till my background sky is just a little darker than I'd like it in the end. I de-star that.

I take the starless and open Curves (This is Ps but I guess GIMP is the same). I place a fixing point on the curve at the brightest point in the background sky. I place a second fixing point below that. If I now lift this curve from just above the two fixing points I'm stretching only the galaxy, which is what I want to do.

Once I've done this, I can do the opposite for the background sky. Again in Curves, I pick the brightest point in the background sky and put in a fixing point. I'll then put a series of fixing points in above that, this time, so all the galaxy stretching will be unaffected. Now I can pick a point below the brightest background fixing point and lift it, so reducing background sky noise. Don't eliminate background noise, it will look oily and false.

Olly

Gonna have to read/research this a lot more,  but it sounds like very good advice. 

When I keep my sky too dark it does look odd/oily as you say.