The Budget Conscious Astronomer: Background Extraction using Gimp 

Thank you for helping many of us with GIMP, especially old farts like me, though zi started in backyard Astronomy at 8 years old and still enjoying it 69 years later.

Wow that background subtracting blew my mind. THANKS

Wow! As a frustrated beginner in AP this was really helpful! Thank you!

That was fantastic. I've been struggling with my backgrounds for months. Many Thanks!!!

Idk. What magic yt employed or which device of mine they spied on but this is the exact video I need.

Thank you

this is a very simple and perfect approach

awesome video

Great video! Learned a lot and will try this on my images.

This is brilliant! thank you so much

very interesting!

Very nice! Am going to subscribe!

Awesome thanks

thanks man!!!!!!!

Very nice!

awsome video worth watching. i learned more from this video then any other

Thank you. It was very interesting. Many people would be interested in getting a complex lesson on processing astrophotos from beginning to end through such stages as DeepSkyStacker, SIRIL, Gimp. And, as an ideal, the use of Topaz Denoise and Topaz AI for additional quality improvement ...

Thank you!

that's very simple ！

Its an interesting approach. I feel like a lot is missed out on tho. It will give a little bit of copy paste feeling, not so natural. I will try it on some of my stuff some day tho :D I usually do this in Siril(Also free) but i do some minor stuff in Gimp before last export.

Blur and Subtract. Now I just feel stupid and need to go back and rework a bunch of images.

So I just did this on a stacked image of the Lagoon Nebula to practice. It was a pretty noisey pic to start with. I don't have the greatest gear. Everything in the vid worked for me. So I tried another stacked image that was cleaner hoping to get a decent pic. Got to the Gaussian blur and the image turned black. I don't really understand. Both stacked images where the same thing basically. Just one was better quality.

Right direction, but uf, is this a ROUGH manipulation of the data... Especially the blurring including the stars! You'll go under zero (bottom clip) for a lot of pixels this way. Better to also replace the stars with background color (select by color -> set appropriate thresholds/maybe extend selection by a pixel or two -> bucket fill), or better yet, make the stars black and use the despeckle tool (so you don't seed a strange local gradient), THEN use a blur filter of an appropriate size (dependant on the background gradient size... Don't smooth out the gradient, smooth out noise). Also, don't subtract the background layer a hundred percent, but slightly less; set opacity of subtracted layer to 99 or 98 or so. This way, you'll prevent clipping a bit better. Your galaxies will show up with much whispier arms, instead of suddenly stopping. However, good news; No need to use GIMP at all for BGE anymore! Siril is great free software that has a sophisticated background extractor. Nico Carver (Nebula Photos on YT) has a nice introductory video on it.