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Martin Pugh
28-12-2008, 01:36 AM
Hey everyone
I hope everyone has had a nice a Christmas with lots of imaging thrown in?

This data is from July and is of SAC B92, a dark nebula in Sagittarius.

Once again, I have taken Ha data (7 hours) and combined it with synethetic luminance to create the master lum. Amazingly, the synthetic luminance consisted of 10.5 hours of RGB data binned 2x2, but the combination has turned out well methinks, and I prefer it to the colour version.

http://www.martinpughastrophotography.id.a u/images/SACB92HaSynLum.jpg

The colour version is here, and consists of Ha+SynLumRGB totalling 17.5 hours in total (7hours lum, 3.5 hours each RGB).

http://www.martinpughastrophotography.id.a u/images/SACB92HasynLumRGB.jpg

cheers and clear skies

Martin

jase
28-12-2008, 01:55 AM
Thats pretty cool Martin! Looks like a cosmic insect or spider (perhaps a black christmas beetle to commiserate the past xmas festivities).

Perhaps marginal resolution loss from the 2x2 data in the synthetic lum, but you seriously can't tell. I'm quite surprised by this. Stars still look tight, undoubtedly from the Ha data. Agree, colour rendition takes top marks. Very well done.

renormalised
28-12-2008, 01:56 AM
Excellent shot....both the Ha and the LRGB versions. Well done:D

Martin Pugh
28-12-2008, 03:15 PM
Thank you.....the HA/Lum combination really is a surprising result here. If you saw the synthetic 2x2 luminance you really wouldnt believe what the combination has produced.....its a good option for forthcoming projects.

cheers
Martin

Kevnool
28-12-2008, 03:25 PM
I really enjoy the coloured version of the image.
So clear and pinpoints.
Well done...cheers Kev.

AlexN
28-12-2008, 06:21 PM
Very enjoyable indeed..

Another nice piece of work Martin.

Alex.

starfinder
28-12-2008, 06:35 PM
Hi Martin. Thanks for sharing your images and giving details of what you've done. Gives us budding image processors insights into how we might improve our own :thumbsup:. Much appreciated. Russ

Craig_L
28-12-2008, 10:24 PM
Remarkable shot Martin - lovely detail and subtle colours. Reminds me somehow of an ancient aboriginal cave painting - the little human-like figure recoiling from the charge of the beast.

Tandum
29-12-2008, 02:05 AM
Martin, How do you create synthetic luminance from RGB data?
Is it as simple as convering to grey scale?

AlexN
29-12-2008, 04:07 AM
Robin, The way I do it (which is probably wrong) is to copy the whole image, paste it in a new layer, in photoshop use Black and white as opposed to desaturating the image.. This allows much more tonal control over the black and white conversion.. I then stretch that data a little more, sharpen it a touch and make sure its contrasty, then right click on the layer, click blending options... Blend as - Luminance. adjust the opacity and fill sliders to taste.. and there you have it.. Synthetic luminance...

Ric
29-12-2008, 11:45 AM
Lovely capture Martin, a fascinating image with great detail around the dark cloud itself.

Cheers

Martin Pugh
29-12-2008, 09:46 PM
Thanks for the additional comments there gents.

Once you have combined all of your RGB frames into a single (synethic lum) frame, you then combine this frame with the master R, G and B
frames to produce a L(syn)RGB.

Then split this into the 3 separate RGB channels, then create a new LRGB using a normal luminance.

HTH
Cheers
Martin