NGC 1333

[Carles]

With Stefan permision, here's the results I got from the stack provided
This one is regular StarTools processing workflow, leaving it as Scientific in color, to me it oversaturates, it is good to get a baseline for White balance, but to me better move it to Artistic and perhaps saturate.

Sin título.png (401.91 KiB) Viewed 16457 times

This one is Artistic, no Decon No Sharp... Just open, autodev, Contrast, HDR , color and Superstructure. --Denoise

result_96900 Sirils Done Contrast.jpg (366.64 KiB) Viewed 16457 times

regards,

Carles

[Stefan B]

Hi all,

Thanks for your feedback. I am currently away from my PC and will answer in detail when I am back home.

Mike, thanks again, looking forward to processing your PI stack!

Regards
Stefan

[Mike in Rancho]

This one is regular StarTools processing workflow, leaving it as Scientific in color, to me it oversaturates, it is good to get a baseline for White balance, but to me better move it to Artistic and perhaps saturate.
This one is Artistic, no Decon No Sharp... Just open, autodev, Contrast, HDR , color and Superstructure. --Denoise

Interesting take also, Carles. Certainly a viable impression. My preference is to reveal that deep rich reddish brown color that some dusty nebula regions can have, whether from long integration, stars nearby, or both. And here at 27 hours we've got that, and so can go beyond the charcoal grey, saving artistic mode for narrowband as designed. Of course saturation levels are subjective to the user and viewer. Scientific strikes me as proper in broadband though, plus I like the crispness and pinpointing that comes out of SVD, especially with Newt stars.

Was that a Siril stack? The ASTAP stack had a lot of color artifacting. But whether LN from PI is worth it or not really depends on the dataset. If not needed (complex gradients mostly), there will be little to no discernable difference. I believe Siril may also employ subframe weighting (not really sure what goes on in the pre-fab scripts) and it did the whole thing in 18 minutes.

Right now I am done with dark nebulae. Emission nebulae for the win!

Yeah, you are probably right. Bright reflection nebula too! Over a couple nights this week I got 6 total hours LRGBHa on vdB 152, and boy there's really little to nothing there. Sigh. That one just may not be made for Bortle 8 (if I'm not 9 at that sky spot) unless I too pick up 20-30 hours.

[Stefan B]

I had a look at the PI stack and had the impression that it is the best stack so far (thanks again, Mike!). Maybe the subframe weighting had some impact. I settled on a rendition between Mike's version and Carles' artistic version:

I also think that the default scientific coloring is oversaturated so I tried to tone that down but also to include the brown color.

Yeah, you are probably right. Bright reflection nebula too! Over a couple nights this week I got 6 total hours LRGBHa on vdB 152, and boy there's really little to nothing there. Sigh. That one just may not be made for Bortle 8 (if I'm not 9 at that sky spot) unless I too pick up 20-30 hours.

Yes, vdb 152 is really hard. I tried once with 20 hrs and failed...not a very nice image was the result (https://www.astrobin.com/zgf136/). I guess that NGC 1333 will be difficult from your location

Still, I just hit the button and let it go.
And go it went. For 7 hours.

Yes, ASTAP took a similar time. I usually stack over night

That would be a pity, Stefan! SV Decon is such a great tool for clarity and most times 1.9 is doing much better than 1.8 for me! I'm sure Ivo will find fixes for these last glitches. My current approach regarding the stars is as follows: using SVDecon tightens the stars so much that I reduce iterations in Shrink module down to 7 or 5. Most times this works fine for me and the result are stars with lots of different sizes. I like that. Using only Shrink with bumped up iterations often results in lots of tiny stars all having the same size.

I have the impression that the new SVD doesn't result in the former "snapping into focus" all over the place but rather selectively sharpens individual stars, but not all of them. And many of the affected stars suffer from ringing. For me 1.8 SVD yielded great results and artifacts were easier to heal. But that may be data and user dependent

I agree on the stars with different sizes. I prefer that over the tiny stars of many images processed using StarXterminator or StarNet etc.

Regards
Stefan

[Mike in Rancho]

Hey Stefan,

Nice image. Sats can of course be turned down even in Scientific color rendering, but I just like it. I think I used 250 and dark sat at 2.5. Could have been lower. I think my only concerns for oversaturation or color bleed was one red star, and that red blob area within the structure. Of course these were 5 minute broadband subs too.

The vast dust, requiring a good bit of stretching I'm sure, does seem prone to some clumping. Maybe I should have dialed back SS some.

I'll try the Siril stack again later at a similar workflow to the PI stack for comparison. Particularly for the speed involved, the Siril stack strikes me as quite good. I'll see what differences I am able to notice, if any.

Speaking of speed - you are right that it seems 1.9 SVD needs a little tweaking or revamping still, but the speed and other improvements over 1.8 seem vast. Hard to go back! Also I was just playing with Ron's Crescent data, running the mono extracts with minimal module use (OptiDev, HDR, SVD), and the target recovered astonishing detail with SVD. It was a "snap" just like you say.

Obviously I was fooling myself on vdB 152, and it would be a bummer if NGC 1333 is similarly faint unobtanium. Alas.

I put one sub each of your lights, darks, and flats into ASTAP to run the SQM tool. SQM 20.58 i.e. Bortle 4.5. Seem about right? Pretty nice especially for the altitude you were imaging.

I then did the same with my vDB 152 data and got SQM 17.93 i.e. Bortle 8.

So to get anything comparable I guess I would need googletegration -- the highest number of subs before infinity.

[Carles]

This one is regular StarTools processing workflow, leaving it as Scientific in color, to me it oversaturates, it is good to get a baseline for White balance, but to me better move it to Artistic and perhaps saturate.
This one is Artistic, no Decon No Sharp... Just open, autodev, Contrast, HDR , color and Superstructure. --Denoise

Interesting take also, Carles. Certainly a viable impression. My preference is to reveal that deep rich reddish brown color that some dusty nebula regions can have, whether from long integration, stars nearby, or both. And here at 27 hours we've got that, and so can go beyond the charcoal grey, saving artistic mode for narrowband as designed. Of course saturation levels are subjective to the user and viewer. Scientific strikes me as proper in broadband though, plus I like the crispness and pinpointing that comes out of SVD, especially with Newt stars.

Was that a Siril stack? The ASTAP stack had a lot of color artifacting. But whether LN from PI is worth it or not really depends on the dataset. If not needed (complex gradients mostly), there will be little to no discernable difference. I believe Siril may also employ subframe weighting (not really sure what goes on in the pre-fab scripts) and it did the whole thing in 18 minutes.

Right now I am done with dark nebulae. Emission nebulae for the win!

Yeah, you are probably right. Bright reflection nebula too! Over a couple nights this week I got 6 total hours LRGBHa on vdB 152, and boy there's really little to nothing there. Sigh. That one just may not be made for Bortle 8 (if I'm not 9 at that sky spot) unless I too pick up 20-30 hours.

I don't really know what Stack was it to be honest, that should be pointed out by Stefan.

About Scientific in Color Module, the thing is that it is an start point to get a good Colour or White balance tone, but don't think it is intended as a end result as per documentation . So, not agreeing at all about "Artisitic mode designed for narrowband" I don't know where did you get that from.

The 'Scientific (Color Constancy)' setting for Style undoes these distortions using Tracking information, arriving at the colours as recorded.

To emulate the way other software renders colours, two other settings are available for the 'Style' parameter. These settings are "Artistic, Detail Aware" and "Artistic, Not Detail Aware". The former still uses some Tracking information to better recover colours in areas whose dynamic range was optimised locally, while the latter does not compensate for any distortions whatsoever.

and

There are a great number of tools and techniques that can be applied in StarTools that let you home in on a good colour balance. Before delving into them, It is highly recommended to switch the 'Style' parameter to 'Scientific (Color Constancy)' during colour balancing, even if that is not the preferred style of rendering the colour of the end result, this is because the Color Constancy feature makes it much easier to colour balance by eye in some instances due to its ability to show continuous, constant colour throughout the image. Once a satisfactory colour balance is achieved you should, of course, feel free to switch to any alternative style of colour rendering.

I use Scientific, for broadband images, to get that White balance calculated by Startools and then switch to "Artistic" to tune up a bit.
The thing is that with Scientific as it is, it is over saturated and it introduces colour noise. So, rather set colour balance Scientific, and move to Artistic, still under Track control, and tweak saturation to taste. About the reds and the gray, it is a matter of saturation, that same image i've posted, if you push saturation, "brown" comes up, but too red is rather noisy.

[Stefan B]

I don't really know what Stack was it to be honest, that should be pointed out by Stefan.

It's been the Siril stack.

I put one sub each of your lights, darks, and flats into ASTAP to run the SQM tool. SQM 20.58 i.e. Bortle 4.5. Seem about right? Pretty nice especially for the altitude you were imaging.

That sounds reasonable. You are right about the altitude. I think in zenith it should be Bortle 4.

Regards
Stefan

[Stefan B]

Speaking of speed - you are right that it seems 1.9 SVD needs a little tweaking or revamping still, but the speed and other improvements over 1.8 seem vast. Hard to go back! Also I was just playing with Ron's Crescent data, running the mono extracts with minimal module use (OptiDev, HDR, SVD), and the target recovered astonishing detail with SVD. It was a "snap" just like you say.

I just player around with some duo NB data of mine. And here SVD worked great. The snap was there again and the little ringing which was there was easy to cure with the focus und fuzz sliders. No reduction of linearity necessary. Maybe there are issues with the PSFs of my broadband stars Ron's data is also dual NB...

Regards
Stefan

[decay]

duo NB data of mine. And here SVD worked great

Maybe there are issues with the PSFs of my broadband stars Ron's data is also dual NB

I can at least contribute that there is no problem with broadband stars in general. I recently added some data to my Iris and took an image of the Ghost and in both cases there has been no problem with ringing. But I still have the impression that it depends on the processing done before engaging SVDecon. I had several runs with one image and in some cases there has been ringing and other times not. But I cannot say in which cases right now.

I wonder if there's something we can do to help Ivo to figure out in which cases there are problems. And to do some coordinated testing with new beta versions.

Best regards, Dietmar.

[Mike in Rancho]

About Scientific in Color Module, the thing is that it is an start point to get a good Colour or White balance tone, but don't think it is intended as a end result as per documentation . So, not agreeing at all about "Artisitic mode designed for narrowband" I don't know where did you get that from.

The 'Scientific (Color Constancy)' setting for Style undoes these distortions using Tracking information, arriving at the colours as recorded.

Whatever appearance you like or that helps you reveal what you want to show is of course totally fine, Carles.

To put things in full context, Ivo's quote also includes -

StarTools is renowned for its Color Constancy feature, rendering colours in objects regardless of how the luminance data was stretched, the reasoning being that colours in outer space don't magically change depending on how we stretch our image. Other software sadly lets the user stretch the colour information along with the luminance information, warping, distorting and destroying hue and saturation in the process.

And I'm also just making an inference from the default settings ST puts in place for us - Scientific Constancy for broadband, and Artistic for Narrowband (probably because there's more leeway to alter this in a false color setting).

Now, I can think of several times where I was processing broadband and put the Style and LRGB Method back (sometimes just one), but I can't think of any image where I took Broadband out of Scientific and went into Artistic.