NGC 1333

[Stefan B]

Thanks to @Mike in Rancho who helped with stacking in Siril after I failed with both ASTAP and Siril ( ) I was finally able to get something out of my NGC 1333 data:

Hasn't been an easy one. Initially I've been totally unable to get a decent stretch with Optidev since there was basically nothing visible but noise grain and after processing everything looked flat and unappealing. Using FIlmdev resulted in a better presentation of the dark dust but the stars were totally bloated.

What saved the day for me was correlation filtering. Usually I never use that since I get better results without it (that's my impression at least). But here I was blown away by the difference the filtering made for the diagnostic stretch. Here's Wipe w/o correlation filtering:

beforecorrelationfiltering.jpg (331.95 KiB) Viewed 16786 times

And here with filtering:

aftercorrelationfiltering.jpg (226.08 KiB) Viewed 16786 times

Also I bumped up locality in Contrast which helped with reducing the flatness of the dark nebula. Additionally the color balance is a bit on the red side but it made the dust look thick and brown.

Anyway, I have expected a bit more since it's almost 27 hrs integrated exposure time but not too bad.

See https://www.astrobin.com/fpg0xk/ for details.

Thanks again, Mike!

Regards
Stefan

[Carles]

Hi Stefan,

you should try adding some "dark anomaly filter" on Wipe. There's a lot of signal there.

Regards,

[fmeireso]

Seeing the result i wonder why the stacking went bad. Were there errors in the capture? I mean , any idea what went wrong?

I never have issues with PI stacking, and should i have issues then it is probably me that made a mistake.

PI is complex and difficult to learn imho, but i do like WBPP alot.
hah yesterday i tried stretching in PI...just could not get that right..

[Stefan B]

Hi Carles and Freddy,

thanks for your feedback!

you should try adding some "dark anomaly filter" on Wipe.

DAF was 15 pixels

Were there errors in the capture? I mean , any idea what went wrong?

In terms of acquisition I used the very same camera settings than for my three most recent images (Caroline's Rose, double cluster, Iris and Ghost). Checked that. Maybe my dark library is a bit on the old side (>1 year) and should be updated. On the other hand I used the same darks for the three mentioned images and they worked...

Mike looked at my ASTAP stack and thought it looks reasonable. Maybe I had wrong expectations. But compared to my Iris and Ghost stacks which are similar targets with a bit less integration time the noise is now much more pronounced.

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

Regards
Stefan

[fmeireso]

Stefan, how do you treat youre stars. I've seen they are always pretty nice without any halo's at all.

I often have that, even on my lately pure dualband picture (so no mix of narrowband and broadband)

[Stefan B]

Stefan, how do you treat youre stars. I've seen they are always pretty nice without any halo's at all.

I think there are often quite some halos, Dietmar also noticed them recently (viewtopic.php?p=14733#p14733)

You can also see them in my recent cluster images (https://www.astrobin.com/habg5n/, https://www.astrobin.com/050lne/), especially around red stars. But I am pretty fine with them. Sometimes they are better (double cluster), sometimes a bit worse (Caroline's Rose).

Processing affecting stars is mostly SVD (although I often skip that now since in my eyes it makes things worse...1.8 was better in that regard for my data sets) and Shrink. I used the Tighten mode with 13 (instead of 10) iterations and also bumped up the sliders for color tame and halo.

But Newts are probably pretty different compared to refractors in terms of halos.

Regards
Stefan

[fmeireso]

I see.

I do mostly pretty much thesame...maybe it is sometimes deconv that makes it worse.

But indeed, could also be the newt verus refractor ...
It still troubles me, allthough sometimes it is worser (or better) then other times

[decay]

Another fantastic image, Stefan! And wow - 20 hours integration time Great to hear that you (and Mike) found a solution for this mysterious problem. I'm curious if you will ever find out what went wrong

Correlation Filtering is a mysterious thing, too Most times it makes things worse but sometimes it saves your bacon. And I've no idea in which cases?! (Well, of course when there's correlated noise. But I don’t know when and why this is the case.) So I just try ...

Processing affecting stars is mostly SVD (although I often skip that now since in my eyes it makes things worse

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.

Best regards, Dietmar.

[Mike in Rancho]

Hey Stefan, here's my quick take after a new stack.

I threw everything into PI WBPP and left all the bells and whistles on, except cosmetic correction. That concerned me for a second, after seeing the results in ASTAP from, presumably, old darks. All else left at default, including VNG debayering. I vacillated between that and bilinear, and while the VNG may soften some crisp detail, their bilinear looked like it might give some artifacts around stars. Don't want that!

It's super easy to do. Siril was also, really. I just renamed the one folder that Siril wants as BIASES to DARK FLATS, and then used directory load. Even without the folder names I think WBPP can figure out what is what, and just automatically sets everything up. But unlike Siril you get a nice window with various tabs and columns/rows like you might see in DSS or ASTAP, only lots better. Still, I just hit the button and let it go.

And go it went. For 7 hours.

But I think it turned out okay. As with Siril I used all 27 hours worth of your lights, and figured I'd just let subframe weighting figure out which shots were good, bad, and how to rank them.

One nice thing about WBPP and the way things turn out after high and low rejection, is that a lot more of the frame seems usable. Basically it rejects out a lot of the stacking artifacts. That means it'll be lower SNR out there, but hey it's the edges, and there are some nice stars to include.

I did a moderately quick and simple ST workflow, bumping the initial stretch a bit, then contrast, HDR, SVD, and Color. I did use SS dimsmall on this. Then shrink but no iterations, just deringing 2px/color tame off on a few of the tiny stars that...rang. Followed by denoise and then a filmdev, but no direct gamma reduction, the DAF setting was sufficient for what I wanted. Might still be a bit too bold?

What a cool target, I must try this one myself.

I think the full tiff coming out of ST looks pretty good, but that's 37MB. The downsampled to 1600px and 92% jpg here...so-so. I uploaded the full size ST image and the PI stack to the same Drive link as before.

Thanks for letting me play with your 27 hour NGC 1333!

Stefan NGC1333 PI-WBPP stack ST9 1B 1600.jpg (607.08 KiB) Viewed 16704 times

[Carles]

Got similar result with Stack provided by Stefan, regular StarTools workflow.