ngc6559, ic 4685

[Geoff45]

Taken over the last new moon session at Wiruna.
Blurb: Shamelessly stolen from the internet
Bright gas and dark dust permeate the space between stars in NGC 6559. The gas, primarily hydrogen, is responsible for the diffuse red glow of the emission nebula. As energetic light from neighboring stars ionizes interstellar hydrogen, protons and electrons recombine to emit light of very specific colors, including the red hue observed. Small dust particles reflect blue starlight efficiently and so creates the blue reflection nebulosity seen near two of the bright stars. Dust also absorbs visible light, causing the dark clouds and filaments visible. NGC 6559 lies about 5000 light-years away toward the constellation of Sagittarius.

Image here https://www.astrobin.com/351685/?nc=user
Larger res here https://www.astrobin.com/full/351685/0/


Acquisition details
Telescope: Plane Wave 12.5" CDK
Mount AP900GTO
Camera: FLI Proline 16803
Exposure: 15 x 600s Ha, 17 x 600s SII, 18 x 600s OIII---Total of 8.3 hours
Processing: PixInsight
FOV: 48' x 49'

[topheart]

Wonderful!
Great details and great colour!
Cheers,
Tim

[Ryderscope]

Fascinating, a great array of colours not normally seen in nebula such as this. Engaging dark tendrils of dust across the image as well :thumbsup:

btw: also happens to be the next image that I was going to target. Will have to find something else now to be original :D

[Placidus]

Superb work, Geoff. Deep and detailed. Very fine processing of the dust.

That's one of our very favourite 'not so often imaged' beasties.

Didn't realize that the blue stuff was reflection nebulosity. We only got what managed to sneak through a 3nM OIII filter, which wasn't much. Now we know.

[RickS]

Woah! I don't think I've seen this up close in NB before. Nicely done, Geoff :thumbsup:

[strongmanmike]

Some nice detail in there Geoff :thumbsup:. I have always loved that snaking black river in this field, so cool, unique even :question:....I think this object looks best in more natural colour though.

Mike

[gregbradley]

I like this rendition. Interesting shades of colour, subtley processed.

Greg.

[cometcatcher]

Very cool Geoff! I've just finished this myself. Just have to process it. How did you integrate the NB into the RGB?

[Geoff45]

Thanks Tim. I was quite chuffed with the way it turned out.


Thanks Rodney. Just do it in the Hubble palet—that will look completely different.





Thanks Mike Trish and Rick. Nice to get a good reaction from the experts

Ta Mike. I agree that it’s the snaky bit that makes this region interesting. It would tend to the boring without it.
How do you define “natural”?

Glad you like it Greg



Thanks Kevin. It’s all narrowband—no RGB. The mapping was
Ha+ 0.35*SII —> Red
OIII —> Green
OIII+ 0.3*Ha—> Blue

[strongmanmike]

Yeah, I know Geoff, hard to define huh..? I guess what I mean is and at least to my eye, some areas just don't look as good in narrow-band (ie without any RGB) as they do in LRGB or even LHaRGB even if you have chanel mixed to approximate an RGB mix :question: Some areas look better in Narrowband than they do in LRGB too, a good example is the fighting dragons and Running chicken areas, both look a little flacid in LRGB compared to SIIHaOIII. The Trifid region is another good example, decidedly drab, even kinda dirty in narrowband (http://arasteo.blogspot.com/2015/08/m20-trifid-nebula-in-narrowband.html) or any mix close to that, looks much better in LRGB (http://www.pbase.com/gailmarc/image/150932230/original).

There are many good examples of what I mean with the NGC 6559 region but just recently Steve Mohr posted an LRGB shot of the same field (https://www.flickr.com/photos/105968790@N03/42763428642/in/dateposted/) taken with the same scope and image scale as yours, so you can compare easily.

Hope that made sense :question:

Mike

[cometcatcher]

Oh okay, cool. Interesting mix, I like it. I need to write this down somewhere for ron...

[Geoff45]

Thanks Mike. I did try the more trad Hubble palet but couldn’t get it to work well. Someone on another forum suggested adding a straight luminance. I will have a go at that when I get the data.

Hi Kevin. There is actually a scientific basis for this mix. See here
http://www.narrowbandimaging.com/synthetic_rgb_page.htm

[cometcatcher]

Thanks Geoff. I'll bookmark that for Ron too as I don't have a mono camera at the moment. I plan on one eventually though.