NGC6979 Losing it's ethereal beauty when imported to Star Tools

[PaulInNorthMichigan]

I have been observing that my Star Tools processing of the Veil Nebula region is throwing away a lot of it's misty beauty and replacing it with something akin of an electrical storm.

My stacking is done in Astro Pixel Processor. I have taken care to use the most favorable stacking settings in APP for further process in Star Tools.

I am sure that there is a lot of software confusion on what is background and what is nebulosity with the Veil region. When you zoom into different areas that perhaps could be confused with light pollution in the APP stacking it actually is whitish nebulosity.

When I do a film process of the Pickerings Triangle area it actually wants to drop all of the nebulosity until you get up to around 99%.

How do you retain the smooth nebulosity without processing it away?

I will show an example area below. I will begin with the APP image and follow it up with my Star Tools processing.

APP.jpg (484.22 KiB) Viewed 4265 times

StarTools.jpg (486.76 KiB) Viewed 4265 times

[Mike in Rancho]

Hi Paul,

Do you have a sample stack and/or a log of what you did?

Without knowing more and just off the top of my head, I would say to try out a less aggressive Wipe, perhaps using the narrowband preset as a starting point. An AutoDev with no ROI, or not much of an ROI. Or, if you need one in order to say, tame 52 Cyg, perhaps adjust the gamma and shadow linearity. Also watch your settings, and adjust as needed, in Contrast, HDR, and Sharp (if used) if you feel those modules are darkening too much of what you feel is legitimate signal and hazy nebulosity.

That said I would have to check out my own data and some reference images, maybe NASA or APOD. I'm unsure how much of the general white fog is actual structure signal compared to just a raised background level or noise.

That said, I agree the second image crop shown does appear a bit harsh and overcooked, possibly even showing spots of black clipping or too much shadow compression, but that can all usually be remedied...

[PaulInNorthMichigan]

Very excellent advice Mike!

I believe that it was all coming apart with the Wipe. I never tried Narrowband before but it minimally effected the structure of nebulosity.

I also never tried taking over a full Auto Develop before, but it held together. I did tweak with the other settings within Auto Develop but they didn't seem to help.

Another tool that wanted to break the nebulosity lines was Contrast. I ended up using the least abusive option.

Color was quite a challenge. I believe I chose a dual band that gave my most even colors.

Normally I brighten the image at Super Structure, but this time I avoided it as it went too far.

I will attach my result. If you think I'm still missing it, I can try some other settings. For my own eyes I think I'm pretty happy, however I do know that the background isn't as dark as before.

NGC6960NGC6979_220805.jpeg (479.79 KiB) Viewed 4248 times

[Mike in Rancho]

Nice one Paul!

It seems you found your ethereal again.

From what I can tell, the overall black point isn't necessarily too bad. If you were to open up your jpg here in like Gimp, and put a pointer in one of the darker spots towards the bottom of the image, the RGB levels are in the teens. I like that. Occasionally I'll go even lower. Some prefer higher, like 25-30, though that might be a bit too gray for my own taste.

Balancing a nice dark outer space background with faint regions of "stuff" is a difficult task, and I can't say I'm all that great at picking the right compromise point. I just eyeball it until I am happy I think.

If you want to try dialing it back, though, you could do a post-tracking FilmDev for adjustments to gamma. After denoise and/or tracking is off, and you've saved your result (so you can reload if needed), just hit FilmDev. You could even open your final Veil result here (hopefully it's a tiff i.e. no compression), and of course choose non-linear, do not turn tracking on. Dropping the gamma level will darken things up and add contrast, perhaps to a level where you find you like both the background darkness while still retaining enough faint detail. If needed, Skyglow can also be used in the balancing process. That slider is just a global pedestal. You can see in the little histogram how the skyglow moves the peaks left and right, while the gamma affects the steepness.

[Stefan B]

Hi Paul,

that looks like a great result - really deep! Would you mind sharing the specs like scope, camera and integration time? Would be interesting to know!

Adjusting the black point is also always a challenge for me...my images tend to have a background which is too dark IMHO, but otherwise it looks blotchy... That is really awesome in your Veil image!

@Mike in Rancho That's been a great analysis of what might help...from only looking at the two images

Regards
Stefan

[PaulInNorthMichigan]

Nice one Paul!

It seems you found your ethereal again.

From what I can tell, the overall black point isn't necessarily too bad. If you were to open up your jpg here in like Gimp, and put a pointer in one of the darker spots towards the bottom of the image, the RGB levels are in the teens. I like that. Occasionally I'll go even lower. Some prefer higher, like 25-30, though that might be a bit too gray for my own taste.

Balancing a nice dark outer space background with faint regions of "stuff" is a difficult task, and I can't say I'm all that great at picking the right compromise point. I just eyeball it until I am happy I think.

If you want to try dialing it back, though, you could do a post-tracking FilmDev for adjustments to gamma. After denoise and/or tracking is off, and you've saved your result (so you can reload if needed), just hit FilmDev. You could even open your final Veil result here (hopefully it's a tiff i.e. no compression), and of course choose non-linear, do not turn tracking on. Dropping the gamma level will darken things up and add contrast, perhaps to a level where you find you like both the background darkness while still retaining enough faint detail. If needed, Skyglow can also be used in the balancing process. That slider is just a global pedestal. You can see in the little histogram how the skyglow moves the peaks left and right, while the gamma affects the steepness.

Mike,

Thank you for the additional suggestions for a more enhanced tweak.

Can you bring in the saved TIFF and do these changes or would this reflect a brand new processing?

[PaulInNorthMichigan]

Hi Paul,

that looks like a great result - really deep! Would you mind sharing the specs like scope, camera and integration time? Would be interesting to know!

Adjusting the black point is also always a challenge for me...my images tend to have a background which is too dark IMHO, but otherwise it looks blotchy... That is really awesome in your Veil image!

@Mike in Rancho That's been a great analysis of what might help...from only looking at the two images

Regards
Stefan

Stefan, I used my ZWO533MC camera for these images. This was using a AT115EDT scope. I believe that I have 200 2 minute images for each of the 2 combined images. It really pulled out a lot of detail. I would like to take a couple more frames to expand the image.

This is like turning a corner to be able to preserve much of the natural beauty in the image.

[Mike in Rancho]

Mike,

Thank you for the additional suggestions for a more enhanced tweak.

Can you bring in the saved TIFF and do these changes or would this reflect a brand new processing?

Yes Paul the saved TIFF should do the trick. I usually make a first save right after tracking is finished, even if I am otherwise going to go do some non-tracking tweaks (could be FilmDev, Heal, Layer...). As I go along I save new tweaked iterations. Load/Non-Linear/Do Not Turn on Tracking takes you back to that same state. It's really only during tracking that saves can get complex and confusing.