Thor's Helmet - Enhanced with Ha & OIII

[marc4darkskies]

Here is the enhanced LRGB version of Thor's Helmet. I added 10 hours of data (6 of Ha and 4 of OIII using 30 min subs).

Seeing never got better than 2.5 to 2.8 (before decon) so using the NB for enhancing the fine detail was next to impossible. It was still great to render the fainter structures though and I like the result. It's quite deep now with most of the frame clearly containing nebulosity and I think I've kept it looking quite natural.

This image replaces my PBase version but below you can see small before and after versions to see the effect.

Full Res - use your browser to zoom in and out:
http://www.pbase.com/gailmarc/image/162574185/original

I have started gathering SII data (so I can do a full NB version) but weather and some equipment glitches (communications with the camera) have stopped me.

Cheers, Marcus

[strongmanmike]

Yah, quite nice, looks alight Marcus and pleasant framing :thumbsup: Look forward to seeing the full NB version, is the SII very strong?

Mike

[Atmos]

Looking good Marcus! Shame about the less than perfect seeing, not that it appears noticeable :)

[Stevec35]

Looks good Marcus. Lots of good detail and nice rich colour.

Cheers

Steve

[RickS]

Much richer, Marcus. Will look forward to the version with Sii!

Cheers,
Rick.

[Placidus]

Quite exceptional, Marcus. I like the colour. It's very deep. There are important bits in the nebulosity that I've never seen before.

[marc4darkskies]

Thanks Mike. See below a small (low quality) stretched stack of SII. It's pretty weak but that's what you'd expect.



Thanks Colin. Yeah, would have been nice to crisp things up a bit more but I'm happy with how it turned out. Good seeing is pretty hard to come by!



Thanks Steve!



Cheers Rick! I'm going to need about 8 hrs or so of SII to do an NB image justice



Thanks a lot Mike! There aren't a lot of other RGB renditions on the web showing the same depth & clarity so I'm pretty happy.

[multiweb]

Awesome colours Marcus. One for the cool wall. :thumbsup::thumbsup::thumbsup:

[marc4darkskies]

Thanks Marc! Glad you think so!

Looks like the pure NB version will have to wait judging by the weather forecast for the next week :sadeyes:

[Peter Ward]

Very slick indeed. I'd recommend that aspiring astro-imagers use this splendid result as a gold standard for the "fat lady's hat"

Velvety smooth structures, excellent intrinsic resolution, great shadow and highlight details, beautiful star colour variation and excellent attention to tracking and focus.

What's not to like?

My only problem with this is I wish I'd taken it! :)

[DJT]

+1 for Peters comment. It's a lovely image and am rootling around with last years data and cant get anywhere near this. Top job. :thumbsup:

[marc4darkskies]

:) Thanks for the kind words Peter! High praise indeed and much appreciated! Layering in Ha well is never easy, but layering in both Ha and OIII and keeping the image looking "real" was a new challenge!



Cheers Dave! The faint structure is quite extensive and surprised me a little to be honest. 30 minute subs (or more) for NB is definitely worth it.

[willik]

That is a very very nice image, not easy to take.

[marc4darkskies]

Thank you Martin!

[gregbradley]

A vibrant image there Marcus. Some red halo's from the Ha/S11 blending around the brighter stars that could be masked out though. That can be problematic in doing Ha LRGB blends.

Greg.

[marc4darkskies]

Thanks Greg. No SII in the image mate. Just blown out stellar profiles in the red channel after stretching the Ha and combining with Red ... and not paying enough attention! Just need to de-halo the red channel stars. Will fix that soon.

[Geoff45]

Good one Marcus. I really like the sharp transitions between the reds and the greens. I don't recall seeing this sort of contrast before.
Geoff

[topheart]

Awesome image Marcus!

I can't see too much of an issue with the stars.....I will take another look.

Cheers,
Tim

[marc4darkskies]

Thanks Geoff! Interesting you should say that because I'm reprocessing completely right now because I too thought the transitions were too sharp between the Ha and the OIII! I have in fact excluded some nuanced Ha signal! I'll post the old and new when I'm done and you'll see what I mean. I still like this rendition but it could be better! :D



Thanks Tim! I think the stars are OK now. I mitigated the halos in the red channel a bit. It will change again when I finish the reprocess.

[alpal]

Hi Marcus,
one of the best I've seen -
it's showing more nebulosity than even the chart 32 image:
http://www.chart32.de/images/phocagallery/galleries/nebulae/thumbs/phoca_thumb_l_NGC2359-V4-2520.jpg
well done.

cheers
Allan

[marc4darkskies]

Thanks Allan!

I have just finished reprocessing the image. I think it is now a more accurate colour rendition in terms of the relativities between Ha and OIII. Below you see small versions of before (image 1) and after (image 2) the reprocess. Sharp transitions are removed and more nuanced Ha is present - particularly in the lower left quadrant. The original PBase image has been replaced.

Combining OIII and Ha with RGB is quite complicated!

[strongmanmike]

Yeah technically better, as you say, better transitions between the Ha and OIII and rings around stars are fixed, a good old fashioned Sidonioing there :D :thumbsup:

Mike

[gregbradley]

That looks great Marcus. A nice repro of what was really only a minor point. But still at this level its those little things that bug us.

Greg.

[marc4darkskies]

Ta Mike.



Thanks Greg. I did the repro because I realized I didn't do the NB layering right, leading to harsh transitions and missing Ha. I let the OIII overwhelm the Ha in the initial version. Worth noting that both signals broadly occupy much the same space. Anyway, this is my first go at using OIII as well as Ha in an RGB image ... always learning!

[deeplook]

Hello Marcus,

your latest version looks the best for me! Very well done, i like that object!

Markus

[Paul Haese]

Either image looks ok to me Marcus. I prefer the saturation levels of the first image but the smoother transitions of the second. Maybe some more saturation might make the second image pop just a little more. Still very nice images.

[marc4darkskies]

Thanks very much Markus!



Cheers Paul. I boosted the PBase version a little earlier this morning with a simple curve to give it more pop but the saturation is the same as before. The sharp transitions were a symptom of less than perfect layering of Ha and OIII and the consequential loss of the fainter Ha information in the first image. Essentially the relativities of OIII and HA in the first version were not representative of the raw data. The OIII in first image also had a slightly too blue look. The second image presents a more nuanced and accurate rendition of colour IMO (while resisting the temptation to go fluro!! ;)).

[gregbradley]

I have also found blending Ha that you can lose some fine detail. My recent SH2-308 bubble image had lots of fine tendrils in the O111 data that mostly were lost in the blend.

Anyone with suggestions to combat that?

Greg.

[marc4darkskies]

I don't know how you process but I can't see how you can lose detail blending Ha or OIII unless the seeing wasn't so good when you gathered the NB data. I had less than average seeing with this image for my Ha and OIII so they didn't significantly add to the fine detail already present in the Lum. Having said that you have to make sure you have a combined LHaOIII (as luminance) such that it represents all three channel's signals well and to which you have applied all your noise reduction and sharpening. I would usually process each separately (L, Ha and OIII) and then layer them for a composite "Super Lum" layer that you will subsequently apply to the colour. However you build the RGBHaOIII colour layer (which is where my problem was with the first version of Thor's), this Super Lum should contain all the detail you need. Hope that makes sense! :question:

[gregbradley]

Thanks Marcus.

I'll try that technique next time.

Greg.

[alpal]

Yes Marcus,
more detail is showing through -
it's almost as if every image is so unique that you have to learn how to process it - without a standard workflow.

cheers
Allan

[marc4darkskies]

What are you driving at Allan?

[alpal]

Hi Marcus,
the processing of images is so complicated that the first try
usually falls far short of the full potential that the data can reveal.
I often have 5 or 6 attempts before I'm satisfied.

cheers
Allan

[marc4darkskies]

Okay, I understand. You're right, it IS complicated and anyone who claims to get it right first go is probably pulling your leg OR under processing their data! The fact is, if you've been in the game a while you have a standard workflow but even then, one size doesn't fit all and each object requires it's own TLC and workflow tweaks. My standard workflow broke with the addition of OIII. All is right with the world now though! :)

[marco]

Fantastic details Marcus and great colors too. I love this object and imaging it with a proper scale as in your case gives it justice :thumbsup:
Great shot
Marco

[marc4darkskies]

Thanks very much Marco!

[Ross G]

Amazing photo Marcus!

On of the best I have seen of this object.

Ross.

[marc4darkskies]

Thanks very much for that Ross! Sorry I missed your remark earlier!

[Stevec35]

Love them both Marcus but image 2 is probably marginally ahead.

[strongmanmike]

Just had another gander at this Marcus and while posting full res always causes me to shrink it in my browser :rolleyes: :scared3: for a good overall look.... I did spend a bit of time surfing the full res, very much fun :thumbsup:

Mike

[marc4darkskies]

Thanks Steve! Yes, the first one is actually under representing the Ha by quite a bit - missing a lot of nuance (my favourite word :))



Hehe, thanks mate! Well, you're supposed to shrink it to look at the big picture ... and then look again at full res to see the even bigger picture! :lol: I'll make you a convert yet! ;)

I rely on good seeing to be able to post full res and this one was on the borderline. The seeing around here is rubbish at the moment too. Hope you and Steve are getting a better deal than I am right now. Between seeing and cloud I've just spent 2 nights gathering 2 marginally usable hours of data for my new project (Antennae).