Annotated Lagoon, 17 hrs, slightly sharper, less artifact

[Placidus]

A very long time since we did the lagoon.

Red: SII 7hrs, Green Ha 5hrs, Blue OIII 5hrs, all 1hr unbinned subs. 3nM. Aspen CG16M on 20" PlaneWave. Stars whitened.

Original image here (www.photos.smugmug.com/Category/Star-Forming-Regions/i-nGtWLvj/0/O/Lagoon%20Ha%205%20OIII%205%20SII%20 7hrs.jpg)


Edit: Reprocessed version here. (photos.smugmug.com/Category/Star-Forming-Regions/i-pWxNk2N/0/O/Sharper%20Lagoon%20Ha%205%20OIII%20 5%20SII%207hrs.jpg) Slightly sharper, slightly less artifact around stars.

It looks much more lagoon-shaped than our previous effort, but we've annotated some other interesting features in the thumb:

A: Flying kangaroo head.
B: Wind god blowing streams of gas
C: Masculine hair dryer
D: Emu
E: Gangly running character from Mad Magazine
F: Soft toy tyrannosaur
G: Mrs Logie
H: Fiery Cliffs

The hourglass is burned out in H-alpha in 1-hour subs. We'll try some 15 minute shots if we get another clear night.

Very best,
Mike n Trish

[Atmos]

I think I actually prefer the tighter FOV in this region. It is wonderfully smooth and very detailed :) Spent a while just looking at all of the gas waves and stuff :P You do have some ringing artefacts around many of the fainter "whitened" stars but it is not overly distracting.

The most important question of all... How long does it take for you to spot all the things :P

[Paul Haese]

I think this colour palette works well with the Lagoon. Nice depth to the image too in my opinion.

[atalas]

And thats what you guys can do with a 20" Mike! as Paul mentioned, lovely attractive colour as well:thumbsup:

[Stevec35]

Looks good guys. I hope my eventual colour version turns out as well.

Cheers

Steve

[Placidus]

Thanks muchly Colin. I'm slowly improving my algorithm for making them go away. The size of the box I automatically put around each star matters a lot and I'm not getting it right with the little ones. Perhaps the little faint ones should be left unbleached.



One at a time they leap out instantly, but I've collected them over many years of staring at lagoons.



Cheers, Paul. It does give an aquatic look to it. We try to stick with Hubble palette, set the zero point accurately from the histograms, and balance the overall colour to be on average neutral.



Thank you Louie!



Thanks Steve, and good luck with your version. Looking forward to it.

[rustigsmed]

awesome detail m&T!

[Andy01]

Veeeeery nice M&T, very nice indeedy.
Sharp, detailed, lots of interest and your nicest coloured image to date imo.
A beautiful Lagoon :)

[strongmanmike]

Ok..I see all but A, B & H...? :question:

A lovely Lagoon :thumbsup: :)

Mike

[SimmoW]

Insanely crisp and deep M&T, and that's just using the IIS image! Very wall-hangable.

[marc4darkskies]

Hilarious M&T! I'll bet when you're enjoying an afternoon cuppa in your backyard every cloud has a letter designation! :lol:

Lovely image with very appealing colours! :thumbsup:

[Placidus]

Cheers, Rusty!



Thrilled you like it, Andy.



Thanks Mike! The 'roo (A) is attached. The other two (B and H) are a bit vague.





Thanks, Simon! We're delighted.



Hi, Marcus! Yes, sunsets are especially narratogenic.

[Atmos]

(A) is a donkey not a kangaroo :P

[gregbradley]

Great shot Mike. I love the framing, depth and structure. The clour differentiates the structures nicely.

Greg.

[multiweb]

Superb field Mike. Up close and personal. Great colour treatment too. :thumbsup::thumbsup::thumbsup:

[RickS]

That's really lovely, M&T! A unique take on the Lagoon. You might want to see someone about that rampant pareidolia though :lol:

Cheers,
Rick.

[Placidus]

You are probably right. My argument was a statistical one, based on the Macropod to Equine ratio outside the living room window. The chap on the left (attached) is the one in the Lagoon. The mum and joey are also cute.



Thanks, Rick. :) But it's all really up there!



Thanks muchly, Marc.



Delighted you like it Greg.

[Atmos]

That's what I see when I get to my rural property! Out my window I see trees, birds and a train line in the distance :P

[Placidus]

Here is a reprocessed version (photos.smugmug.com/Category/Star-Forming-Regions/i-pWxNk2N/0/O/Sharper%20Lagoon%20Ha%205%20OIII%20 5%20SII%207hrs.jpg) with a gentler magenta ring reduction algorithm that produces less artifacts.

The old algorithm tried to guess what was "under" the star from the surroundings. The new algorithm tries to model the star as a radially symmetric structure around a centroid which can be different for each channel.

I've also added a bit of hopefully justified wavelet sharpening.

Best,
Mike

[Atmos]

The detail in the core is very nice and whatever sharpening that you've done really works for it. Some of the dusty (black) regions appear 3D compared to the nebulosity behind it.

No ringing artefacts :thumbsup: Your previous algorithm appeared to handle the stars better in general, whether it is that algorithm or another one that does that I am unsure. The brighter ones appear more bloated, some of the magenta ones (moreso towards the north west) have halos and there are some smaller stars throughout the image that appear to have been saturated but have no lightness to them (more like small red splotches).

I don't think the above were in the original. Your new algorithm works an absolute treat with some of the artefacts that the previous one created, not sure if the new one is creating some other problems if whether it is something new entirely.

The detail around the central region in your image is far better than what I've achieved in mine! (just did a comparison)

[Placidus]

You have very sharp eyes, Colin. Thanks for taking the time to look. Not sure I can do much better on the stars for the moment. I'm out of ideas. It's much, much harder than one might think. Very glad you like the image as a whole.

[Atmos]

It is a lovely image, don't get me wrong :) What I was pointing out are on minor things. It's that last few % that can be the most painstaking, learning that from experience :P

[strongmanmike]

I probably agree with Colin's comments but never the less this is an excellent wavelength ordered emission line image of the Lagoon guys with plenty of detail and delineation between the three wavelengths, nice job. The fact that it was processed completely with your own software makes it rather incredible really :thumbsup:

Mike

[Placidus]

Well put, Colin, and much appreciated. Slowly we learn.



Thanks Big Mike. We didn't use a mask for the stars when sharpening, because we didn't want to confuse the effects of the mask with the effects of the whitening. That was probably a mistake. But we're much encouraged by your overall assessment. Will keep working on the problem, using other images.

Cheers!

[Placidus]

At last we're happy with this. Inspired by Fred V, we went starless, separating each channel into stars and background. Colour balanced and wavelet sharpened the background. Then dropped in the original H-alpha stars as white.

To go starless, we used a dual approach: (1) model the bright core as radially symmetric about a centroid, and remove that. (2) Use multiple linear regression (3rd order polynomial with cross products) to model what should be "under" the star from the background, and feather heavily. (speaking of which, the 3 chooks are still laying an egg a day each).

The nebulosity is pretty much as before, but the stars are far less intrusive. They're all there, but smaller, fainter, and slightly better resolved.

Time to put our pen down on this one.

Original image here. (www.photos.smugmug.com/Category/Star-Forming-Regions/i-MgKjwG8/0/O/Lagoon%20Ha%205%20OIII%205%20SII%20 7%20via%20starless%20processing.jpg )

One vague possibility with this sort of approach is to try to guestimate the star's plausible temperature and therefore colour from the OIII to H-alpha ratio. Something for one of those rare rainy days perhaps. :)

Best,
M & T

[Atmos]

Can I give a double :thumbsup: ;) Actually went to reprocess my M8 data recently to get closer to your colour calibration but I think I may have accidentally deleted everything except the Ha data :/

Was surfing through the exquisite detail and did find one lost green mark, presumable one single star that was removed but not replaced. Not visible unless you actually go detail surfing though :thumbsup:

Benchmark shot MnT :)

[Placidus]

Thanks muchly, Colin. Your thoughtful input has provided us with much needed moral backbone when devising an algorithm despite repeated setbacks. Sorry to hear about your possibly evaporated OIII/SII data.

Still hoping, weeks later, to do some short 15 minute subs for the Hourglass, but 'the rain it raineth every day'.

[gregbradley]

I like the sharpened image. Nice job.

Greg.

[Placidus]

Thanks, Greg!