Duet along the galactic plane – NGC6357 and NGC6334

[jase]

Hi All,
I am pleased to present the galactic plane wanderers NGC6357 and NGC6334 (http://www.cosmicphotos.com/gallery/image.php?fld_image_id=108&fld_album_id=11).

Within the constellation Scorpios, two magnificent nebulae wander along the galactic plane of the Milky Way galaxy. Four 7th magnitude stars perfectly aligned point to the center of the faint emission nebula NGC6357 (left in frame). The nebula forms the shape of a crab and is approximately 5500 light-years distant. A feline footprint marks NGC6334 (right in frame). It’s commonly known as the Cat’s Paw nebula.

Both NGC6357 and NGC6334 nebulae are close the the galactic plane and as such are hidden by galactic dust which makes them difficult to observe visually. The galactic dust decreases the blue and green wavelength emissions (colour extinction). This is evident by the stars within the nebulosity – there are no obvious signs of bright blue stars commonly found in star forming regions. The galactic dust particles are selectively removing blue light – a phenomenon known as “interstellar reddening”. The dust particles have very little effect on red light wavelengths hence the nebulae glows vibrantly in the hydrogen alpha emission line.

Info on the image and processing;

Total exposure time: 4.2 hours (Luminance:105min, R:50min, G:50min, B:50min). The image is an LLRGB composite. This object is best suited for Ha imaging, but looks still impressive with strong luminance data. May revisit to get Ha data another time. Thanks glenc for the nebula listing - these two objects pair beautifully in the frame of the FSQ/STL11k combo.

Subtly different routine from that what I normally do for LLRGB images. Typically, I use the PS shadow/highlights tool to perform the non-linear stretch on the RGB data, but this time I used DDP as I felt it was more suited to the strong luminance info. I still manually stretched the luminance data with PS levels and curves. The luminance data was placed through two iterations of LR deconvolution. A few PS layer masks created in the routine – a star only layer, two nebula layers to manage colours and finally a high pass. Noise reduction also performed through an inverted layer mask.

OT: Please note that I’m updating my gallery web code and as such image links to my previous posts will become invalid. I will update what I can in due time. The new code improves image scaling and management amongst other things. I’m not happy with the PHP GD library that handles the dynamic resizing of images as it introduces a lot of compression artifacts. If I can’t get the results I want, I will revert back to my original code. I will continue to work on it when I get the time. Minor disruptions may occur during the upgrade period - sorry for any inconvenience.

Thanks for looking. I hope you enjoy it. All comments welcome.:)

[duncan]

As usual Jase, TOP NOTCH PHOTO!
One of these days i'll get to start,LOL.:thumbsup:

[Garyh]

Hi Jase,
Always enjoy your work!
I don`t think I could pick fault with any of them, except they are reaally masterpieces in every respect...:thumbsup:.
beautiful!!!
cheers

[Dr Nick]

3 letters, WOW! ;)

[sheeny]

Exquisite, Jase!:thumbsup:

Al.

[strongmanmike]

Hi Jase

This is another fine image coming form your beautifully paired equipment.

The framing is great, and fitting both those nebulous complexes in one FOV is awesome.

You have said all comments are welcome so I'd like to comment (not critisise) that I find this and some your previous images just a bit lacking in intensity and vibrancy, they look just a little flat? It is as if the layering and shadow highlght tool you are using PS is washing them out just a tad..?

Still, excellent images of course :thumbsup:

Mike

[little col]

:eyepop::eyepop: amazing :thumbsup:

[jase]

Cheers Duncan. :thumbsup:



Thanks Gary. Appreciate the kind words.:)



Cheers Dr. Nick:)



Thanks Al.:thumbsup:



Thanks for the critique (“comments”) Mike. :D Very good - am pleased you’ve picked up on my imaging style. I don’t over saturate or “bake” my work for too long. For RGB work, I prefer the “natural” look compared to the vibrant/vivid colours, like those found in a box of smarties. This is one of the points which defines my images from others. I use the PS saturation function predominately on the star processing routine, but seldom for other tasks. I feel there are better ways of bring out colours in nebulosity. The PS Saturation function is actually performing a linear stretch on your data, so your bright areas are only going to get brighter depending how hard you push for colour – this may not be the desired result your after. In comparison, the PS Shadow/Highlights performs a non-linear stretch allowing much greater control. You can also set colour correction in the process – big advantage. Of course, this is a matter of opinion and preference. Everyone has their own methods and style. Appreciate your input.:thumbsup:


Cheers Col :thumbsup:

[Ric]

A wonderful image Jase, you have framed it perfectly.

Very nice work

[jase]

For the masses...

Got broadband?

Here is a less compressed version to wet the taste buds.
2400x1800 (5.7Mb) (http://www.cosmicphotos.com/reprocessed/NGC6357%20and%20NGC6334.jpg)

This is not the full frame version (4008x2745 delivered by the STL11k). If you want to see that one, you'll need to buy a print from me :whistle:

Enjoy the ride!:D

[little col]

:eyepop:well i never knew the human brain could handle so much information!!!

[iceman]

Beautiful image again Jase, I think it's great that you resist the urge to pump up saturation. It's very easy to overdo things in post-processing, I've done it many times myself :lol:

I can see a lot of compression artifacts in the original linked version, so thanks for the hi-res one!

[jase]

Thanks Ric. It is indeed a double target for the focal length.


Cheers Col. Never under estimate the power of the mind. <Fade in spooky close encounters music>



Thanks Mike. Yes, it is easy to over do it. I spent one too many hours processing this one. Trying different routines etc. It’s kind of like being an author and proof reader in one – you need a break in between the two roles to see things in a different light (fresh eyes). This is why I enjoy posting images here for comment - I consider all comments. I’ll leave reprocessing it for a cloudy night or full moon. I may collect some Ha data and layer it with the current luminance to see what else I can bring out. Never a dull moment.

I just couldn’t bring myself to show a “waxed out” version, full of nasty jpeg artifacts. Certainly not how I envisage displaying my imaging efforts. Am hoping to get time to rework the web code over the weekend to address this.

Thanks again all.

[Bassnut]

Well, what can one add. Imaculate guiding and focus, tastefull, natural processing. A little wide field for my tastes, but thats OK ;-).

So where do you go from here?. Given the low ST11K QE, perhapes even longer subs for a deeper view. You have a NABG CCD, you can do it. Not a critisim, just you have reached a platoue, what else can you do?.

Cheers Jase, as expected, top work.

[jase]

Fred! Dude, you’ve been awfully quite lately (no posts). What’s happening? I wait with abated breath for a “killer” image magnificently tracked with the new Paramount ME of yours.

Thanks for the comments.

The journey is still young – much to learn and experiment. I've had positive comments on my images from the SBIG yahoo group, so I guess I'm heading in the right direction (you may have seen the posts). Indeed, longer subs is the way forward when using the NABG chip such as the KAI-11000M. I currently use 15 to 20min subs for luminance work and 10min subs for chrominance, but depends on the target. Getting fair results with this camera/filter/scope combination. I’m doing some mosaic work at the moment which I’m finding challenging/time consuming. Might also investigate combining the best data from multiple focal length instruments, i.e. a wide field view from the FSQ coupled with data from a longer focal length targeting specific objects in the frame. Reached a plateau? Nah, very far from it.