Lagoon Nebula:- Processing test.

[sjastro]

Lagoon nebula.

3 hrs Ha, 1 hr R, 1 hr G, 1 hr, B. BRC-250 STXL-11002.

I am investigating a new procedure where full contrast of the Ha luminance image is not compromised in the final colour image by processes such as blending the Ha and R data to preserve colour balance.

High resolution here.
http://members.iinet.net.au/~sjastro/Lagoon_test.jpg

Steven

[gregbradley]

That looks very good Steven. Lots of detail yet good colour.

Greg.

[Rod771]

Yes, very nice detail.

Looking good :thumbsup:

[strongmanmike]

Yeah, great details there for sure, an amazing area in high res.

The silver stars with rings could be worked on, maybe cut and paste the RGB stars back in?.. aaaand the decon is a tad obvious in the bright areas, other than that great stuff :thumbsup:

Mike

[Andy01]

Which HaRGB process is that your're using? Is it one of these?

http://starizona.com/acb/ccd/software/ps_hargb.aspx????

http://www.robgendlerastropics.com/HARGB.html

Just curious as I gave a talk to the ASV guys on this topic last week.
cheers
Andy

[Geoff45]

Amazing detail Steven. One of the best I've seen.
Geog
Ff

[atalas]

Lovely Steve.

[sjastro]

Thanks Louie.



Thank you Geoff.




Andy,

Neither technique was used.
The objective was to avoid any blending of the Ha and R data to form a new luminance as some contrast is lost when compared to a straight Ha luminance.

The procedure is to process a HaRGB image in PixInsight. This does a good job in maintaining star colours without any HaR blending.
The resultant image however has the typical salmon pinkish colour of using a straight Ha luminance.
The pinkish colour is removed by using the shadow highlights command in Photoshop in reverse as is the usual processing procedure.
Here the shadows correction is set to 0%, while the highlights tab is shifted to the right until the pink is removed.
Further tweaking of the colour balance is done against a straight RGB reference.

I have used this procedure on this NGC3247 (http://members.iinet.net.au/~sjastro/ngc3247Ha.html) as well.



MIke,

Strange the decon is a bit obvious as no deconvolution was used. Only a touch of a wavelet filter was used.



Thanks Rod




Thank you Greg.

Clear skies

Steven

[strongmanmike]

Ah I see, I guess the wavelet function can impart a similar look to heavy deconvolution if applied a little too aggressively then..?

Still an interesting exercise in processing otherwise :thumbsup:

Mike

[gregbradley]

:lol: Is sharpening and decon the new "noise":rofl:

The silver halos around some of the brighter stars is something that could be repaired most likely. I wonder what caused that.

As I recall there was another Ha blend image recently that had trouble with halos around stars from the Ha and that was from PI. Is there some setting in PI (PI always seems to have millions of obscure settings in their tools dialogue boxes) that corrects that? Cutting and pasting stars back in most likely won't handle it as those rings are larger than the stars. Probably needs a star mask done before that step to protect them.

Greg.

[strongmanmike]

Noise..? what is that? :question: :lol:

[RickS]

I noticed some decon like artifacts too. Nice processing otherwise, Steven.

[sjastro]

Thanks for the feedback.

Here is a more restrained version.
http://members.iinet.net.au/~sjastro/Lagoon_test1.jpg

Clear skies

Steven

[strongmanmike]

Sorry Steven but the detail still really "looks" artificially wormed :shrug:

The stars look better now though :thumbsup:

Mike

[alpal]

Hi Steven,
that's great data.
Don't worry about what others say about sharpening -
I think every image can be lifted by a little sharpening -
it gives the eyes something to focus on.
I would have processed the brighter middle part like this.
I hope you don't mind?
I played around with colours & contrast with curves & masks.

cheers
Allan

[sjastro]

No problems Alan.

Regards

Steven

[sjastro]

Any better now?
http://members.iinet.net.au/~sjastro/Lagoon_test2.jpg

Clear skies

Steven

[gregbradley]

I like it. Pay the Vets fee and you are all clear!

Greg.

[RickS]

Looks good to me!

[multiweb]

Sweet shot. Looks very good.

[strongmanmike]

Yes, now the detail looks real and the stars have improved :thumbsup:

Mike

[sjastro]

I'm going to have to take out pet insurance on getting rid of those worms Greg.:lol:



Thanks Rick.



Thanks Marc.



Those deworming tablets worked fine Mike.

Clear skies

Steven

[sjastro]

I've decided to add one final process to the image.

It is a stretching function I developed in Pixinsight where the pixels are mapped to the following function newpixelvalue = oldpixelvalue*exp(-0.2*oldpixelvalue).

This function allows the fainter areas to be stretched without increasing noise in the background.

High resolution here:
http://members.iinet.net.au/~sjastro/Lagoon_test3.jpg

Clear skies

Steven