NGC6357 narrow band

[Paul Haese]

This object has been on my redo list for 4 years now and I am finally getting around to doing the data collection on it. This is an intial image but there needs to be another two session at least to make this image what I have in mind. For now the colours are fairly reasonable but I want more of the hubble palette look to it.

Click here (http://paulhaese.net/ngc6357.html)for larger image

Feel free to comment or critique.

[gregbradley]

Love the colour of the neb. 6357 is dead boring in LRGB so this is a very nice way of presenting it. It looks very interesting in NB.

The magenta stars, whilst a Hubble way of doing things isn't that appealling. Have a look at selective colours tool and see what you think:

Magenta

cyan +60%
magenta -100%

Blues
Yellow +60%
back +60%

See what you think.

Which filter is giving the reflection halos?

Greg.

[Paul Haese]

Will take a look at that Greg, thanks for the tip.

The reflection is on all three. I might have to send Astronomiks an email and see if I can get mine exchanged. I could use the halo reduction though in the final image and prevent stop the problem.

[Paul Haese]

Uploaded with your suggestions Greg. Looks pretty good, thanks for the tip.

[Peter Ward]

It's on my re-do list as well....a very a faint bugger and hard to do justice to.

I like your latest rendition a lot :thumbsup:

[TrevorW]

Very nice Paul not overpowering

[Paul Haese]

Thanks guys. Yes a tough one, but one with lots of interesting detail. A real good one for NB.

[Bassnut]

Very cool indeed Paul, excellent.

[alan meehan]

What a lovely shot Paul ,heaps of detail in there,cant recall seeing this one before looking forward to more data .
AL

[RobF]

Will be interesting to see where you go with this Paul. Already looking very striking. Not one I have any experience with - the "War and Peace neb" I gather.

[Paul Haese]

Thanks guys, appreciated.

Alan, there are some great examples on the net of this object. Martin did this several years ago with striking results. It appears to be a great narrow band target.

Rob, yep it is the "War and Peace" neb.

[midnight]

A striking image Paul.:thumbsup: Lovelly structure.

Darrin...

[dugnsuz]

Love the detail in the nebula but not the light violet/magenta bright stars - an unavoidable part of NB imaging?
Minor gripe as it is a great image
Doug

[Rigel003]

Great result with lots of detail and interesting texture. Even though the lobster is a little billious in colour, I'm pleased to have been present at it's birth. The halos are quite substantial for not especially bright stars.

[Paul Haese]

Thanks guys.



For Hubble palette alone I think it is unavoidable. I will eventually include RGB for star colour and this will for the most part remove the problem. At least I think so.

[avandonk]

Very good detailed image Paul.

I am not at all an expert on combining NB data but my years at Kodak where they drummed colour theory that is basically human vision response to light is still with me.

Magenta stars tells me the stars in the red and blue channels are far too bright for the green channel. This is most probably due to getting the SII (red) and OIII (blue) nebulosity up to near the level of the HA (green). This is the Hubble pallette?

The continuum filter that Astrodon sell would solve this problem by just subtracting some star intensity from SII and OIII NB data before combining with HA NB data.

Have I got this correct or am I just dreaming?

By the way in additive colour, magenta is the absence of green. Have a look at a colour negative and all the trees and green plants are magenta!

Bert

[Stevec35]

Don't think I've ever seen this nebula in narrowband before Paul and I like your treatment of it. I suppose the magenta stars are a minor distraction but they don't detract from a very nice image. With RGB stars I think you're going to have a real winner.

Cheers

Steve

[Peter.M]

I can see him!

[wysiwyg]

Paul,

Its a good effort and an intersting object, however the image is still very noisy. There is something very funky going on with the stars, not talking about the magenta aspect of them but the different halo sizes. This could be CA?

I think to improve this image, you may need to devote either more time in processing or longer subs to try and stabilise the noise.

Cheers
Mark

[Moon]

Paul,
I really like the colours too.
Yes there is some noise there, but you've stretched it to the max so we can see some really faint stuff, so I guess that's to be expected.
Overall, quite a good image :-)
James

[Paul Haese]

Thanks guys.

Bert you are right in that I reduced the green channel markedly to produce the hubble palette. The resultant by product is these magneta stars. Many Hubble images have them. To get around the issue RGB stars can be masked in over the narrow band data. The filter option might be possible as I have one spare filter space left.

Mark, if you read my initial post I say that it needs two more sessions yet to get the noise down. I fully agree there is a lot of noise. I used scale darks which could have contributed to the noise but will use same time darks for the next run. This is 7 subs per channel but I think given the dimness of the target it probably needs something like 21 in each channel and maybe even more in the OIII data. I am currently collecting data on several objects and all with narrow band data. Just running this one around a bit. Next time the image will have a marked improvement.

The Halos are most likely from defective filters and not CA. An Apo from Takahashi is not known for CA. I bought the filters second hand those might have been from an older batch that had problems with halos. Astronomiks were replacing those filters. I am tempted to get them replaced under the original agreement. It depends on whether the company will play ball on this. Replacement with RGB stars will make a huge difference to the look of the image.

James you picked it. This data was stretched twice to pull out this detail.

[cventer]

Nice work Paul. You beat me to it.

I have imaged this same object for 3 nights a few nights back and have a fair bit of data so I am keen to see how it stacks up. Has to wait though as I have a narrowband Eta I need to finish and am dealing with same magenta star issue.

[LucasB]

That is a beautiful image Paul. I agree that the colour scheme is great for this object.
Lucas

[stevous67]

Some tuff critics out there, this image is of a high standard. Good one Paul.

Steve

[Paul Haese]

Thanks guys,



No, that is fine, critique only improves the imaging analysis and that is good for the general standard. :)

I am hoping that in a couple of sessions this image will really shine.