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Old 16-12-2011, 08:04 PM
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Eta Carinae

First real image here with my new toy.

Taken over last 2 nights in Melbourne

Scope: FSQ106
Camera: SBIG ST-2000XM
Mount: Paramount MX
Location: Glen Iris Melbourne

25 x 5 min Ha
3 hours RGB

Attached are resized Ha Luminance and RGB frames

large Version on HaRGB here: http://www.dslrfocus.com/gallery/ETA-HaRGB2-Large.jpg
large Ha Lum Only here: http://www.dslrfocus.com/gallery/ETA-Ha-Lum-Large.jpg

Still struggling with blend of Ha and RGB to get nice red without Salmon hues.
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Click for full-size image (ETA-HaRGB2.jpg)
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Last edited by cventer; 16-12-2011 at 10:39 PM.
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  #2  
Old 16-12-2011, 09:26 PM
Mighty_oz (Marcus)
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Nice, good start to the fsq Clouds are away today so i'm going to do some PA and try to get a pic of something in orion, after your shot it's made me ichy again. Keep them coming there's never enough FSQ images hehe
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  #3  
Old 17-12-2011, 08:50 AM
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prokyon (Werner Probst)
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The Ha image is a stunner!
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  #4  
Old 17-12-2011, 01:31 PM
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A fabulous Ha image there Chris.

I find this procedure works well with Ha (there are other methods this is one).

1. Do your RGB or LRGB image as normal. Register the Ha along with the LRGB so they are all aligned. You can align in Photoshop but its a pain and hard to do precisely.
2. Process the Ha by itself, levels,curves, shadows/highlights, selective sharpening etc. I would suggest making a duplicate layer of the Ha and set the top layer to soft light to increase contrast and use the opacity slider to suit. This reduces the background noise as well which will help later. Even an S shaped curve to increase the highlights but suppress the noisy background. Again later on that noisy background can mean red noise in your final image if there is no LRGB data in the same pixel. Save it as a tiff.
3. In Photoshop after you have finished the LRGB image create a 2 new layers and copy and paste the Ha into them. If you shot the Ha at 2x2 binning then resize it to match.
4. Set the blending mode to lighten on both.
5. On the first layer Click on channels and holdng down control click on green and blue channels and they go blue.
6. Control A (to select) then control delete to delete. Now you are left with only the red channel. Name that channel Ha as red
7. Use curves to boost. In lighten mode only the pixels that are lighter than the main image show through. So if you don't boost with curves generally not much comes through. So boost to taste. I sometimes make a duplicate layer and set it to saturate blending mode to boost the red if needed or simply make a duplicate layer of the Ha as red layer after that layer is boosted with curves but you want more. Slide the opacity slider to suit.
8. On the 2n layer do the above but leave the blue channel and delete green and red. I set the opacity on this level to suit but usually only about 10% to 15%. It creates the H beta colour which is magenta/blue.


I also sometimes make a layer mask of the stars so that the Ha does not affect the stars. You can attach that to the Ha as red and Ha as blue layers.

This is the same really in effect as adding Ha into the red channel and saving it as a blend but you have much more control and can change it to suit.

I also find running a noise program such as Noise Ninja is helpful on the Ha image as it tends to be noisier than LRGB images.

I also have tended over the years to keep Ha in check as it easily overwhelms an image and a pleasing image usually has a more equal blend of colours rather than just one, in this case red. So I prefer it to be more of an enhancement and slightly subtle is better than too heavy.

Some add Ha as luminance to sharpen details but you will find it creates salmon colours easily and washes out RGB colours rapidly and for very little gain. If you do add it you simply create another layer and set it to luminosity blend mode and adjust the opacity to suit. Sometimes it adds a bit of detail otherwise lost as RGB is not that great for showing sharp details.

The above is one way. Adam Block details doing Ha on his tutorials and its rather complex. I suppose you would get used to it and I am used to the above which is what Tony Hallas uses and I was using it like that before I saw his tutorials. Lighten mode is the key. Keeping the Ha background out of the image can also be important as it can add a lot fo background red noise to your image or pollute star colours. Lighten tends to prevent it from attacking stars as the RGB stars are brighter than the red Ha ones.

Greg.
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Old 17-12-2011, 01:42 PM
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Thanks for info Greg

Will give that a try a report back.

Cheers
Chris
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Old 18-12-2011, 12:54 PM
Stevec35 (Steve)
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Beautiful Ha image there with a real 3D quality to it. I agree with everything that Greg says about blending Ha and RGB. Sometimes though you can get some benefit from using the Ha as a luminosity layer but you generally have to have an opacity less than 30%. It's just a matter of trying various blends until you get something that works.

Cheers

Steve
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  #7  
Old 18-12-2011, 02:18 PM
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multiweb (Marc)
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Not too keen on the blend but I really like the mono version. Nice and sharp.
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Old 18-12-2011, 03:54 PM
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DavidTrap (David)
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I like the detail in your Ha image, but wonder if you've stretched the mid tones a bit too far. I think this is costing you a bit of contrast in the image. Personally, I find it hard to get a pleasing dynamic range in Ha images.

Any suggestions from the gurus would be appreciated!

DT
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Old 18-12-2011, 05:09 PM
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mill (Martin)
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Nice ha image and i have to agree with what David said, the midlevel is a bit over stretched so it washes out some of the detail.
To get redder reds you can try to saturate the color picture a bit more and then blend it in.
You can go back and do less or more saturation.
Martin.
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Old 18-12-2011, 05:33 PM
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mill (Martin)
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Just did a bit of processing on your image if that is ok.
Processed the mid tones with shadows/highlights.
Then used select color range and selected the hilights and then used color balance to get a bit of blue in the bright part only.
Then levels to knock the red back a bit and then gave the stars a little bit of a color boost.
With all this there is a bit more nebulosity in the shadows and tightened up the mid tones for a bit more detail.
That is all i could do with my limited knowledge on a jpg.
Hope you don't mind.
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  #11  
Old 18-12-2011, 06:36 PM
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Quote:
Originally Posted by mill View Post
Just did a bit of processing on your image if that is ok.
Processed the mid tones with shadows/highlights.
Then used select color range and selected the hilights and then used color balance to get a bit of blue in the bright part only.
Then levels to knock the red back a bit and then gave the stars a little bit of a color boost.
With all this there is a bit more nebulosity in the shadows and tightened up the mid tones for a bit more detail.
That is all i could do with my limited knowledge on a jpg.
Hope you don't mind.

Martin Nice job. Thanks for that. I like that MUCH better. When you see version this you can see I pushed the mid tones way too far.

I will have a go at this myself now. May need more info on steps you followed.
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  #12  
Old 18-12-2011, 06:37 PM
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Quote:
Originally Posted by DavidTrap View Post
I like the detail in your Ha image, but wonder if you've stretched the mid tones a bit too far. I think this is costing you a bit of contrast in the image. Personally, I find it hard to get a pleasing dynamic range in Ha images.

Any suggestions from the gurus would be appreciated!

DT
David

I agree. I did not see it myself but seeing martins repro shows that for sure.

Funny how when you stare at something for so long you really need an external eye to tell you the obvious of what is missing.
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  #13  
Old 18-12-2011, 06:39 PM
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Quote:
Originally Posted by multiweb View Post
Not too keen on the blend but I really like the mono version. Nice and sharp.
Thanks Marc.

I agree the Ha is better the the RGB blend.

I still ave a lot to learn about blending RGB and all the photoshop tricks.
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  #14  
Old 19-12-2011, 06:19 AM
Ross G
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Great photos Chris..very sharp.

I really like the monochrome shot. It has excellent detail.


Ross.
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  #15  
Old 20-12-2011, 03:42 AM
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midnight (Darrin)
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The Ha is very nice and rich Chris. Some very good tips there from the guys so have read this thread with great interest (if I ever get down the mono path.....)

Well done.

Darrin...
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  #16  
Old 21-12-2011, 12:05 AM
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Did a bit of messing about with tips from here tonight as well as on these 2 posts

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

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

I am happier with this color version but still not totaly happy.

Large Version here: http://www.dslrfocus.com/gallery/Eta-Repro-Large.jpg
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Last edited by cventer; 21-12-2011 at 12:46 AM.
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