The Western Veil

[Stefan B]

After a kind of short AP hiatus due to real life stuff I've been able to get some time under a clear and dark sky, went for the Western Veil and captured some duo NB and broadband data:

I am not too happy with it. The faint structures don't look very pleasent and the star field drove me crazy. Tried different approaches with NBaccent among them. In the end I cropped the image to focus on the Witch's Broom (the original FOV included some structures from Pickering's triangle) and used the l-eNhance data for luminance and UV-IR cut data for chrominance. The duo NB data at least had less and tighter stars to begin with. Shrink had a lot of work with this image and I used the entropy module for the first time. It gave quite some emphasis on the OIII data which is the best part of the image IMHO. Maybe I'll use that again in the future.

Best regards
Stefan

PS. For technical details see https://www.astrobin.com/s9ek7s/.

[fmeireso]

Does not look that bad at all.
Maybe a tad too much stretch and a little bit less saturation. IMHO, still no expert in all this.

The very busy starfield is a pain in the neck in that region indeed. Difficult to deal with.

I find the nebulae self quite nice but the bottom left nebulae remnants look a bit washed out.

Not so easy to process. I am struggling with the other part NGC 6992/5 . Made several versions, a HOO version i posted on CN, but did not get much likes, so i guess, it is not good at all.
I had issues with the temperature , never had such a hot night which produced alot of noise, this time i had to take darks that helped a bit.

[Stefan B]

Thanks for your feedback!

Maybe a tad too much stretch and a little bit less saturation.

Agreed I repeatedly face the problem that initially the second stretch looks fine in black and white but the impression is different after the color module. But stretching again after contrast, HDR, sharp and SVD often does not work for me.

In terms of saturation I like the saturation of the broom but it's too much for the fainter parts. Matter of taste of course. I should have left the saturation low during the color module and increase it in SuperStructure only for the brighter parts. I already worked a bit like this but probably not enough

The very busy starfield is a pain in the neck in that region indeed. Difficult to deal with.

Thanks for confirming that

I find the nebulae self quite nice but the bottom left nebulae remnants look a bit washed out.

That's my impression, too. That's why I cropped away most of the stuff from Pickering's triangle. The fainter stuff lacks integration time and is stretched too much (see above).

I am struggling with the other part NGC 6992/5 . Made several versions, a HOO version i posted on CN, but did not get much likes, so i guess, it is not good at all.
I had issues with the temperature , never had such a hot night which produced alot of noise, this time i had to take darks that helped a bit.

Would you mind posting a link to the image. I'd be interested, especially in the star field In terms of temperature I am really glad that I have a cooled camera now. With these temperatures and the banding of my old DSLR the image would have been a complete mess.

Thanks again!

Stefan

[fmeireso]

This is a version on astrobin,not HOO, normally processed , taken with a L-enhance and limited integration time.

https://www.astrobin.com/p4kyde/

Second a HOO version placed on CN, click on the link for the png, better resolution.

https://www.cloudynights.com/topic/8338 ... cygne-hoo/

But as said , on CN it did not get much attention.

Taken with an unmodded DSLR. Of course now i have to take a mono DLSR Ha shot to use as luminance to get more nebulosity.
I am not quite finished.
But anyhow i struggled to process it, also because of the heat and uncooled DSLR and well the busy starfield. Star color is lost, due to the L-enhance filter...i saturate them to white otherwise they are ugly cyan blue..
I am not satisfied either with both results, it is perhaps not that bad, but ...not yet good enough imo

[Stefan B]

I like the rendition on CN. But it's maybe stretched not enough? But therefore the star field appears well controlled. Overall a great image with only two hours of integration time

Regards
Stefan

[decay]

Hi Stefan,

the OIII parts of Witch's Broom look awesome! The fine details really seem to glare, absolutely fascinating, I could watch at them for hours. And it is not that bad, that the fainter parts of the nebula apart from Witch's Broom are a bit blurred and desaturated, this leads the eye of the observer to the Broom. It looks a bit like that miniature effect used in photography.

And despite to the fact, that you are not satisfied with it, once again you have managed to create an overall neat looking background, even this mottling we often see, seems to be under control as much as possible . Do you apply any kind of post processing outside of ST? Maybe some kind of blur effect?

And the combined processing with RGB data for colour and in order to get true star colours seems to work like a charm as well.

I’m a little shocked that 8 hours of total integration time is not enough for this target ?! It must be really dim. And why is the Ha part so much weaker than the OIII part? Has it something to do with the duo-band filter and bayer matrix of your OSC or is Ha really weaker than OIII in this case?

Best regards, Dietmar.

[fmeireso]

I like the rendition on CN. But it's maybe stretched not enough? But therefore the star field appears well controlled. Overall a great image with only two hours of integration time

Regards
Stefan

Stefan,

Reread the thread on CN. Actually using Starnet, there is a way of reducing the starfield or let say stretch the nebulae more and the starfield less...

I tried it, i think this opens perspectives.

[fmeireso]

. And why is the Ha part so much weaker than the OIII part? Has it something to do with the duo-band filter and bayer matrix of your OSC or is Ha really weaker than OIII in this case?

Best regards, Dietmar.
[/quote]

Dietmar,

I think that is just the nature of this object. I am working on the other pasr NGC 6995/2 and i took some Ha lately...not impressive and i could not use it as luminance cause the L-enhance stack was just better. So i concluded that the OIII part in the nebulae is just stronger than the Ha part. In many other nebulae just the opposite is true...

[Mike in Rancho]

Nice! I love this target.

But it is not necessarily easy. And with such a busy starfield, I think any broadband here stands to be troublesome.

And while OIII in the structure seems strong, as Freddy notes, I believe that with OIII you can also pick up a lot of background noise. In my recent mosiac, the Ha was still the cleanest. My kludged together OIII, and the weak SII, required separate aggressive Wipes.

This SNR also has areas of bright structure, and faint structure, that takes more integration to show properly. In my case with limited integration, those parts really didn't show up.

[Stefan B]

Hi Dietmar,

thanks for your kind words!

Do you apply any kind of post processing outside of ST? Maybe some kind of blur effect?

I do some tweaks after final denoising in ST, but nothing to do with denoising. In PS I apply a bit of local contrast enhancement with the Astronomy Tools Action Set and a bit of color/saturation manipulation in the Lab color space.

I’m a little shocked that 8 hours of total integration time is not enough for this target ?! It must be really dim. And why is the Ha part so much weaker than the OIII part? Has it something to do with the duo-band filter and bayer matrix of your OSC or is Ha really weaker than OIII in this case?

Well, I only had four hours for luminance/detail. Broadband maybe doesn't count really. But I've been surprised, too. Nonetheless, the OIII filaments are really bright. Ha on the other hand is rather faint. I guess that's just how it is after looking at some images. Probably it's not the duo NB filter since it usually has no problems picking up Ha as with the Butterfly nebula for example (https://www.astrobin.com/03tcxw/).

Regards
Stefan