IC5146 – The Cocoon Nebula

[jase (Jason)]

Hi All,
With the clouds slowly parting as the monsoon season draws to a close, I’ve managed to acquire a quick set of data to complete another image. So, without further delay, I’m pleased to present IC5146 – The Cocoon Nebula

About the target;
The Cocoon Nebula (IC5146) is located in the constellation Cygnus and resides 4,000 light years away. This remarkable nebula is intriguing in that it has emission, reflection and absorption characteristics due to dust particles in the region. The nebula is also a stellar nursery harbouring an open star cluster containing approximately 80 young stars in which some can be partly seen through the folds of nebulosity.

About the image;
The image is an [Ha+L]+LRGB composite consisting of 2.5 hours total (Ha:60min,RGB:30min respectively) taken from the Lightbuckets 24” RC (4876mm F/8), Rodeo – New Mexico. Four data sets were created: synthetic lum which was created from the RGB filtered images as I didn’t collect any luminance data on the rig, Ha, RGB ( w/ratio of 1.11:1.0:1.04) and a DDP stretch (hard stretched) RGB. Ha and lum placed through two iterations of deconvolution to handle the oversampling (.57 arcsec/pixel) and generally tighten the image. I created the synthetic lum to manage the Ha data integration considering the Ha data has very tight small stars, it’s difficult to match broadband filtered data. The synthetic luminance was blended in as lighten mode on top of the Ha layer in PS. Subtle adjustments were made to the opacity to bring it together. Not a huge amount of RGB data given the total integrated exposure times which made stretch the data hard. The synthetic luminance on the other hand was fine as I didn’t need to stretch the data too hard to being out the stellar profiles. The RGB data was put through neat image using layer masks to keep stars intact, but controlling noise. I found it complex to integrate the Ha data into the RGB. In most cases I’d blend 10% or so into the red channel, but the Cocoon is different target, one of which I’ve never handled before. As its part reflection, part emission, integration of Ha+R dominates the image. So I took a different approach by progressively blending the Ha data into the synthetic luminance. This process was performed three times, each time opacity was increased along with saturation so I could monitor both histogram and general aesthetics. I do however feel I lost some of the blue reflection nebulosity in the process. To circumvent this, I introduced another layer being the DDP stretched RGB. This layer was stretched rather hard, almost to the point of clipping, then heavily boosted in colour saturation. At the top of layer stack it was integrated as a soft light blend. As soft light is a darkening function, its important the data is stretched reasonably hard. I then altered the opacity looking for any form of data clipping in the RGB channels. – none present. Subtle selective contrast masking was performed to bring out the highlights and darken specific features, followed by minor colour balance tweaks to the shadows. Seasoned to taste. Don’t feel I managed the stars very well, but it works. A few internal reflection problems with the green filter due to a bright star off the edge of frame. I desaturated the area, but was not enthusiastic about chasing it due to a possible upset of the dusty regions.

Anyway until next time, Enjoy!

Cheers

[Dennis]

Hi Jase

Whilst I haven’t previously made a detailed study of this object, I cannot recollect ever seeing an image that generates so much of an apparent 3-D effect. I feel that I could simply fall into the soft clouds of nebulosity, to be cocooned in their enveloping cotton wool-like softness.

Top stuff Jase – keep ‘em coming, although I’m somewhat pooped from reading about your exhaustive workflow and processing description; makes Ben Hur look quite un-epic like!

I’m still shaking my head at the 4876mm focal length….wow!

Cheers

Dennis

[dcalleja]

Jase
I really appreciate your detailed info on post processing. It really helps the rest of us.

Oh - and the image is brilliant by the way

[jase (Jason)]

Originally Posted by Dennis

Hi Jase

Whilst I haven’t previously made a detailed study of this object, I cannot recollect ever seeing an image that generates so much of an apparent 3-D effect. I feel that I could simply fall into the soft clouds of nebulosity, to be cocooned in their enveloping cotton wool-like softness.

Top stuff Jase – keep ‘em coming, although I’m somewhat pooped from reading about your exhaustive workflow and processing description; makes Ben Hur look quite un-epic like!

I’m still shaking my head at the 4876mm focal length….wow!

Cheers

Dennis

Thanks Dennis Enjoy reading your poetic responses. I concur, it does look like a glorified cotton wool ball. The ha data while strong, doesn't contain much in the way of hard detail. Undoutedly due to the dusty and reflective properties of the area. This wasn't an easy one to process. I think it would look interesting in narrowband.Maybe an idea. Its well placed at the moment for northern hemisphere folks. The processing is rather standard with exception to Ha integration being an iterative LRGB process. The soft light blend may have boosted the saturation a little too high I feel, but if you google this target, you'll note that many other images have a "lollipop" feel to it. Need more data to bring out the expanse of the region overall - 2.5 hours is minimalistic. Thanks again for checking out the image and making comment.

Originally Posted by dcalleja

Jase
I really appreciate your detailed info on post processing. It really helps the rest of us.

Oh - and the image is brilliant by the way

Thanks Dan. Providing the processing info is no problem, I typically make notes as I go along so I know what I did and if it works, I know what to do again. The routine is not rigid or "mechanical". The decisions to do what and when is usually target based. Pleased you liked it.

[Bassnut (Fred)]

Exceptional image there Jase, on checking some other top efforts on the Cocoon, you have handled the processing very well, it beats them, and the blue nebulosity came out nicely. The Synthetc Lum looks natural too, the RGB quality was ample. Theres an overall softness about it, but better that than noise, its very clean.

A pleasure to view.

[Garyh]

I agree with Fred there!
Many images of this object seem overly red biased but you have bought out all the delicate hues in this one and keeping the colors soft and very natural.
Beautiful work Jase!

[beren]

Awesome image Jase, as always the work-flow commentary is great even though its beyond by grasp

[jase (Jason)]

Originally Posted by Bassnut

Exceptional image there Jase, on checking some other top efforts on the Cocoon, you have handled the processing very well, it beats them, and the blue nebulosity came out nicely. The Synthetc Lum looks natural too, the RGB quality was ample. Theres an overall softness about it, but better that than noise, its very clean.

A pleasure to view.

Cheers Fred. Appreciate your feedback. Just made some subtle adjustments, I probably should have given it 24 hours rest before I posted the image after processing. The more you look at it, the more you can see things which could perhaps been performed better. I'm happy the way the synthetic lum integrated actually. Something reasonably new to me. I've seen other imagers use it with mix results (or perhaps something else went wrong, so I should be judgemental). Thanks again.

Originally Posted by Garyh

I agree with Fred there!
Many images of this object seem overly red biased but you have bought out all the delicate hues in this one and keeping the colors soft and very natural.
Beautiful work Jase!

Thanks Gary. Yes, I looked at some of the other work others have done on this target, but well after I had commenced the processing. I don't particularly like viewing other images before-hand as the mind starts playing games pushing you towards a biased view of what the object is suppose to look like. I prefer to simply let the processing take me there...thus creating a unique and personal impression. Thanks.

Originally Posted by beren

Awesome image Jase, as always the work-flow commentary is great even though its beyond by grasp

Thanks Beren. Pleased you liked it. Don't worry about the processing blurp, its just for those who are interested - just enjoy the end product Thanks for taking the time to view and make comment.

[avandonk]

Not bad Jase. I try to keep up with your sagas of the convolutions and deconvolutions used to tweak the image to your satisfaction. I will only say this once (sorry 'ello 'ello) this is fine for a narrow field but for wide fields we are limited as to what manipulations we can use to 'bring out detail' as it looks incongruous compared with the rest of the image. I know this is an unfair comment as we are not comparing like with like.

All the same though your image shows you cannot beat aperture and good data followed by intelligent processing and presentation.

Best image I have seen of this object. But I don't get out much

Bert

[jase (Jason)]

Cheers Bert. Yes, wide fields and deconvolution don't always agree. Comes back to your arcsec/pixel sampling too. Though one thing I enjoy with wide fields is hybrid imaging - adding data from a longer focal length instrument to give the image depth. Here is an example. TOA150 was used for deeper luminance. The FSQ was used for RGB and the overall wide field panorama. So you're not always limited by wide field imaging. I find it good to strike a balance between narrow and wide. Processing is different between the two, though there is still the foundation of knowing what you wish to convey through stretching etc. Thanks again for your comments. Much appreciated.

[rally]

A truly beautiful looking image Jase,

And a nice illustration of the fact that a good final image can also be a function of the skill, effort and black art of post processing.

I am always curious - how did you manage the G2V star in this one.
Even the selection process is something I will yet have to master.

Thanks for sharing.

Cheers

Rally

PS - for White Balance I mean

[gregbradley]

A sensational image Jase masterfully processed.

Greg.

[theodog (Jeff)]

Great image jase.
I like the dark dust detail -just a hint of reflectivity.
Well done.

[multiweb (Marc)]

That's a great shot! Reminds me a bit of the trifid.

[RB (Andrew)]

Another stunning image Jase !
The high res version is beautiful and I just love the blue hues of the wispy neb on the right up against the rosie Goliath of the Cocoon.

[sjastro]

Excellent image Jase.

Steven

[jase (Jason)]

Originally Posted by rally

A truly beautiful looking image Jase,

And a nice illustration of the fact that a good final image can also be a function of the skill, effort and black art of post processing.

I am always curious - how did you manage the G2V star in this one.
Even the selection process is something I will yet have to master.

Thanks for sharing.

Cheers

Rally

PS - for White Balance I mean

Cheers Rally. I'm pleased with the results considering the small quantity of data. Really, this target is best acquired through just a luminance - no Ha filtered data, hence I was rather dependant of the results of the synthetic lum to bring the reflection nebulosity through.

Good question, with G2V on rental scopes you typically go by the guidance of the rental operator. Many use Astrodon filters which are seen as easier considering their 1:1:1 colour balance ratios. Operators suggest using these "default" ratios to get you close to the right balance and it does, BUT if you're looking for greater accuracy you need to delve deeper. Rarely are the Astrodon filters a true 1:1:1 ratio on a given optical system. For this image, I didn't acquire any G2V subs, instead I referenced information from the SSRO-S/PROMPT team. They use a couple of 16" RCOS with Apogee U47's and Astrodon filters in Chile. The E2V CCD-47-10 AIMO back illuminated chip in the U47 has near identical spectral response to the Lightbuckets Apogee U42 that has the E2V CCD-42-40 Ceramic AIMO back illuminated chip. Their G2V tests reveal an RGB of 1.11:1.00:1.04 using SAO 163948 8.5 magnitude at altitude 75 degrees. I have also made an assumption that the optical coating between the two RCOS are similar. So there you go, no trickery to obtain these figures, just referenced existing information on hand. Again, thanks for taking the time to check out the image and make comment.

Originally Posted by gregbradley

A sensational image Jase masterfully processed.

Greg.

Thanks Greg. Much Appreciated.

Originally Posted by theodog

Great image jase.
I like the dark dust detail -just a hint of reflectivity.
Well done.

Thanks Jeff. Indeed the dark dust in and around the main complex is interesting. There is a mass of reflection nebulosity around the key feature, however was difficult to extract without more data.

Originally Posted by multiweb

That's a great shot! Reminds me a bit of the trifid.

Thanks Marc. Pleased you liked it.

Originally Posted by RB

Another stunning image Jase !
The high res version is beautiful and I just love the blue hues of the wispy neb on the right up against the rosie Goliath of the Cocoon.

Cheers RB. Yeah, the faint reflection nebulosity adds an extra dimension to the image. The image characteristic reminds me of another image I worked on - The flaming star nebula. Undoubtedly the pinkish hue on the Cocoon is due to much of the reflection nebulosity, compared to the more pronouced deep vibrant reds of Ha emission. Thanks again for checking and the image.

Originally Posted by sjastro

Excellent image Jase.

Steven

Cheers Steven.

=====
Thanks to all those who have commented. I appreciate the acknowledgement.

[Alchemy (Clive)]

Sure is tough at the top end of the imaging game, you know everyone is having a look with the fine toothed comb, but once again you have produced an image that is enjoyable to look at, i dont understand the fine details of the processing being a one shot color user, but the stars look good to me (not sure why you dont like them).

[strongmanmike (Michael)]

....amazing close up that! Very nice work with that lill'ol 24" Jase

That was a nice short exposure and probably fairly affordable huh? Can't you please tell use the cost of taking it? Pleeeease? Would be very useful info

Mike

[Babalyon 5]

Great image and excellent processing. So, the average cost of the image is $400ish just for the 2.5 hrs? Wow!!