Light pollution removal in GIMP

[chiralchemist]

Hi there. Finally managed to get some clear(ish) skies a few weeks ago and started out with some widefield shots, since I hadn't managed to get my cheap CG3 mount in working order at that point (it is now - all I need is a clear night... ). Anyway, I took the following using a 10 second or exposure at 400 ISO using a Canon 1100D with a 50 mm prime lens @ f2.4. Took 10 shots, with appropriate flats, darks, etc then stacked with DSS, and used it to do some initial manipulation of the image with the result below.

I've noticed that in the bottom right hand corner, I've started to get some light pollution. I've searched and found a few ways to remove this in Photoshop, but not in GIMP.

Since the CG3 is now waiting for a clear night, I'm expecting more of the same problem, so can anyone point me in the right direction of how to deal with this?

Thanks in advance

[chiralchemist]

OK, sorry, I posted the wrong image by mistake.

Try this one...

[Cozzy]

chiralchemist,

the few ways you found how to do this in Photoshop you can do in Gimp, they are very simular software, look in the help section in GIMP for gradients hope this helps. I'm sure there will be others with more knowledge of this process popping in to help as well.