Remove green noise

[ffgoas]

Hello,
I have been using SharpCap for close to three years. It is my main setup, capture and process program. I admit I am a lazy photographer, no flats, usually no darks. Just a extension of my observing with an image saved. I also to quite a bit of outreach. Popular question, "How come it is so green?" Sometimes I can play the histogram in live stacking but I just don't get it all. I can take saved images and run them through Siril and "remove green noise". Corrects it good enough for me. In Siril they call it "Subtractive Chromatic Green Noise Reduction". No idea how it works but it just about fixes enough for me. Any Ideas to emulate that process? It will clear up M13 stars almost perfectly and the dumbell will go from green to blue.
Thanks!
Brian Doyle

[Xio1996]

That's spooky, I uploaded a video on YouTube today describing the same problem! Well, not a problem as such, more how using Siril to remove the green noise from images in an EAA session. Take M27, decreasing the green noise with Sirl really improves the contrast of the dust/clouds. On M13 it was more of an aesthetic process. I likened it to adding a filter to your eyepiece to improve the view. Applying the process manually took a little over a minute. In fact less time than some EAA'ers allow for a single sub exposure.

Have fun.

Pete

[ffgoas]

Saved as seen ( with best color balance in stack hist0gram )

Stack_30X240sSec_300_crop.jpg (741.95 KiB) Viewed 1376 times

one click in Siril - pretty quick on my pc's - didn't really think about horsepower

Stack_30X240sSec_300_crop no green noise.jpg (740.25 KiB) Viewed 1376 times

Pretty dramatic.
Brian Doyle

[admin]

Hi folks,

thanks for the pointers to this being easy in Siril - once I have SharpCap 4.1 out of the way I will be looking for new features for the next version and will definitely look into the possibility of doing this.

cheers,

Robin

[Tiago Ferreira]

I just crank down the green in the histogram color and never, ever, saved a green tint image of a star cluster. Did you try that?

[Gfischer]

I use the gradient pre process which helps me a lot with the green noise. Probably due to bad light pollution. To bring out more nebula I stretch more than I probably should. The green noise will show again. I use gradient reducer in astrosurface on saved image to bring back to darker background.

George

[ffgoas]

Sorry for the late response. I normally use the color balance in the stacking histogram. If i reduce the green the image goes purple. Maybe if i took a more AP approach and used flats it would help. As i am using this as a observing means the closer to set up and look the better. I do fuss with the image but not to the expense of why i am doing this. I also use this as an outreach tool.
SharpCap allows me to see objects thru modest equipment that i normally would not see. I normally use a 8inch sct, reducer and asi294mc.
Brian

[Cey42]

+1
I try this using the green channel but the results are not as good as I would like.

Cey