M16 suggestions

[Cheman]

Hi all.
I've been going back and forth with this image and cant get the color to my satisfaction. In this version, I let the color module do its thing and got this

not real happy with it, even tried to desaturate a bit, still not what I like. Then I tried the color module masking the stars in to try to improve them without modifying the nebula and got this

I likethe nebula better but not the star colors so much. Maybe I should try blending the two? I've seen so many different color versions on the interwebnet that look so vastly different from each other. I'm not trying to match any other image, but am a bit stumped by this one.
Here is the dropbox link if anyone wants to play with it. https://www.dropbox.com/s/8a1fknl88wo6x ... 1.fit?dl=0
Its a stack of 78 3 minute subs, QHY8 color ccd, Meade 12"ACF with AP reducer.
thanks for looking
Che

Edit:Hmm, there has been a fire to the south of my location the past few days. No visible smoke in the area I was imaging, but that doesnt mean there were not any smoke particles up there, this could be contributing to my difficulties,

[Cheman]

So I tried again, and toned things down a bit. Stars look better to me.

what does anyone think?

[Landbo]

So I tried again, and toned things down a bit. Stars look better to me.

what does anyone think?

Absolutely the last run. It is without doubt a very difficult object and process. I do not think the star's color is so realistic as they could be. But ???

Even ended up with something similar before Star Tools took a trip around Jupiter for me. I'll try another day, it's bedtime now.

Best regards, Leif.

[admin]

Yep, your last version is what I would expect M16 to look. Give-aways that you're onto a good color balance are the nice star temperature distributions.

The image is quite soft though and can really use some Decon - I suspect seeing and/or transparency wasn't too great at the night?

Did you take flats for this one?

Autosave001(1).jpg (303.9 KiB) Viewed 8440 times

Used a very simple/generic workflow for the above.

File loaded [/home/irwjager/Downloads/Autosave001(1).fit].
--- Auto Develop
AutoDev to see what we got. Can see some vignetting, noise, data is quite soft.
--- Crop
Parameter [X1] set to [54 pixels]
Parameter [Y1] set to [42 pixels]
Parameter [X2] set to [3022 pixels (-18)]
Parameter [Y2] set to [1993 pixels (-23)]
--- Bin
To convert softness into less noise, while making it betterr suited to using Decon.
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Wipe
Vignetting preset.
--- Auto Develop
Final stretch.
Default values.
--- Deconvolution
Parameter [Radius] set to [2.2 pixels]
--- Wavelet Sharpen
Using same mask we used for Decon
Parameter [Amount] set to [200 %]
--- Color
I had similar problems to you with the color calibration. It's like the green channel has some slight anomalous data in it. Did you use flats?
Used MaxRGB color balancing - for this and other techniques, see http://www.startools.org/modules/color/usage.
I still had to 'cap green' to yellow. I'm wondering what is going on...
Parameter [Dark Saturation] set to [5.60]
Parameter [Saturation Amount] set to [104 %]
Parameter [Green Bias Reduce] set to [2.77]
Parameter [Cap Green] set to [To Yellow]
--- Wavelet De-Noise
Default values.

Cheers,

[Cheman]

Hi Ivo
thanks for the input on this one. I did use flats, scope was set up exactly as for my M51

in which the color came out much to my liking. I only binned at 71 % and did not use decon as I saw no improvement. Seeing was not great, sort of breezy, and its a bit of a job keeping focus on the SCT in our n hemisphere summer here in the high desert of Nevada with wild temp swings and M16 was still pretty low to the horizon. As I stated, there may have been some smoke contributing to this as we've been having a major forest fire in the general area. In what way would smoke effect the color balance. I would suspect it would tend to make it more red(orange), but thats just a guess based on our colorful fire sunsets. I will try to process again with 50%bin and also use decon, but i suspect I may just need to capture new lights with the next moon cycle.
Thoughts on the smoke??
Thanks again
Che

[admin]

Hi Ivo
thanks for the input on this one. I did use flats, scope was set up exactly as for my M51

in which the color came out much to my liking. I only binned at 71 % and did not use decon as I saw no improvement. Seeing was not great, sort of breezy, and its a bit of a job keeping focus on the SCT in our n hemisphere summer here in the high desert of Nevada with wild temp swings and M16 was still pretty low to the horizon. As I stated, there may have been some smoke contributing to this as we've been having a major forest fire in the general area. In what way would smoke effect the color balance. I would suspect it would tend to make it more red(orange), but thats just a guess based on our colorful fire sunsets. I will try to process again with 50%bin and also use decon, but i suspect I may just need to capture new lights with the next moon cycle.
Thoughts on the smoke??
Thanks again
Che

Smoke acting as a natural red filter; you might well be right actually! Given what was in the image and the calibration techniques used, the image kept tending to red more than I'm used to. Very interesting; I always learn something new!

[Cheman]

I think I may have to be satisfied with this revision with this data. Deconv helped once I increase the radius parameter as Ivo did. Learned something there

Will for sure try to capture new data once the fire is out and see if it makes a difference
Che

[mhamburg]

My God, Che! That is a gorgeous image. M16 is one of the objects I aspire to get, but is usually so low in elevation. I image at about 42 degrees N in lousy seeing northeast skies. But I will persist!
Michael

[Cheman]

thanks Michael. I'm at 39 north, so you should be able to give it a go.
Che