M42 6 hours Narrowband

[DavidNg]

Hi,

This is the "Green" version of Orion nebula (M42) in Ha, SII and OIII bands. About 6 hours of exposure with FLI Proline, Astro-Physics 155 + AP field flatterner. Captured with CCDAutopilot 5 through Maxlm. Guided with Takahashi 60 FS and Starlight Express Super, Paramount MX mount. Processed with PixInsight and PhotoShop CS6. Bias, Dark and Flat frames calibrated. Diffraction spikes are artificial, I like them though.

Taken on the nights of 25 September and 24 October 2013. Backyard observatory, Turramurra, Sydney.

High resolution at Astrobin: http://www.astrobin.com/62743/
Thanks for looking.
David

[alpal]

Interesting shot but it looks over sharpened.

[Bassnut]

Overprocessed to hell, but different, nice change to the usual overwhelmingly yet again boring RGB.

[strongmanmike]

Going to be honest here David, it looks pretty ummm? :question: Yuk :scared3:

It has the hallmarks of the things one would expect from the great gear used buuuut I think you should have another tinker, love to see what else you might come up with so put it up here when you do :thumbsup:

Mike

[Bassnut]

Luckely, you can ignor Mike, as many many do. Granted its crap in some ways, but I like your thinking on his one. All the hallmarks of budding "astro art", bugger the purists, youll get there.

[strongmanmike]

Yup, definitely drinking :drink:

[alpal]

I think the raw data stacks of: Ha, SII and OIII, would be excellent.

I'd like to have a go at processing it.

[DavidNg]

LOL, I happened to discover something in PixInsight called LocalHistrogramTransformation, gave a couple of runs :) will definitely control my excitement. Thanks for your advice



LOL too, I watched too much PI on Youtube and tried them all on this image.



Thanks Mike, much to learn I am. Thanks for you valuable comments. Will try to process this one again surely.



Sure alpha, Please have a go :) Perhaps write down what are your steps too for us novices to follow!

3 raw files Ha, O and S are at Astrobin Rawdata http://www.astrobin.com/rawdata/publicdatapools/9/

[alpal]

David,


Thanks David,
I had to join AstroBin to download it so I uploaded my result there too.
Have a look here:

http://www.astrobin.com/62930/

I had to do a lot of stretching & also sharpening at 4 pixels to get any detail out of it.
Maybe others can try?

cheers
Allan

[gregbradley]

Its a striking image David. As mentioned the most obvious processing issue is its oversharpened. Sharpening is best done selective with a mask as it can be quite a destructive process.

Greg.

[LewisM]

Loving that data! I ended up doing a sigma reject, with a Catmul-Rom, and then a Sum-Median stack - all CCDStack of course.

Decided against colour (green... no thanks!), went grayscale.

LOTS and LOTS of detail! I had to upload as a jpeg - Astrobin is having an issue with png's at the moment. Hence some image artifact.

Lay off the fake diffraction spikes though David - the beauty of a 155mm AP refractor ruined with fake diffraction spikes :) I dunno, never like seeing M42 "hanging" - I had to rotate it 180°

http://www.astrobin.com/full/63029/0/

[LewisM]

Took a deep breath, and tried colour. I ended up using 3 layers - a false Ha, a false OIII and false NII (based on the real data, just altered)

Histogram is whacky, but as Allan mentioned,it needed some serious manipulation to extract detail. No channels ended up aligned.

Come on Mike, tell me it's crap :)

http://www.astrobin.com/full/63030/0/

[strongmanmike]

No actually, it would make a wonderful bathroom tile or ceramic piece, seriously :). So yes, as a monochrome art work it does look quite striking but as an astronomical image...I dunnooo :question: needs more colours and variation I recon :thumbsup:

[alpal]

Hi Lewis,
You've done well.
Your versions are much brighter & more vibrant.
I knew the data had some promise.
Let's see if Mike can do better? :)

cheers
Allan

[LewisM]

Agree. As has been mentioned many times before, green does not belong in space :) I have NO intention of ever using an nitrogen filter personally. M42 looks YAK in green.

I am going to replace colours and see if I can come close to an RGB with it :)

Can't deny the data is good though Mike.

[DavidNg]

As others have suggested I tried without green and without sharpening it too much :), I don't understand why green (Ha) signal is so strong?

[alpal]

That's an interesting result.
Maybe I should have another go?

cheers
Allan

[DavidNg]

If you have time alpal, would love to see what others can come up too. Thanks in advance.

David

[alpal]

Hi David,
I got an interesting effect by reprocessing with swapped Hubble palette.
Now Ha = Red, SII = Green & OIII stayed Blue.
It was reprocessed & then added approximately 50% opacity with the
last pic with normal Hubble palette.
It was then rotated & cropped.
A lot of great detail came popping out.

See here:

http://www.astrobin.com/63180/



cheers
Allan

[troypiggo]

Isn't Hydrogen the most common element so makes sense it's more abundant? Have a look at the exposure times that the narrowband gurus like Fred V use. Hours and hours on just SII. Need that to get the signal/noise ratio up so it can be stretched enough to match the Ha.

[nebulosity.]

I had a try with Nebulosity,

Something a bit different, O111 (red) S2 (green) Ha (blue)

Jo

[DavidNg]

Thanks Nebulosity, certainly different look and steering away from the unpleasant green.:thumbsup:



I used 2 hours each, thanks for letting us know, will try more data in S and O. As I remembered using similar ratio to process Trifit nebula, the green signal was nowhere as strong, perhaps M20 has different composition.


Love the new colors Allan, great suggestion of images combination. I will try that too :thumbsup:, Thanks David

[alpal]

David,


Thanks David,
If you don't like green - who does? -
then you can always swap Ha for red.
I think the pic came out in quite agreeable colours.

cheers
Allan

[troypiggo]

Here a quick roughy showing Hubble palette (SII to Red channel, Ha to Green, and OIII to Blue) a little more balanced. I was trying to get some blue/cyan and yellows in there. You'll notice when you do that, the stars come out magenta. This is because the Ha in G is so dominant, you stretch the heck out of R and B giving magenta in the stars if you want the nebulosity to be balanced.

Couple of ways to achieve this in PixInsight. For this one, I took your 3 masters, using the LinearFit tool I adopted the Ha as reference image and applied the LF to both the SII and OIII. Then just do a LRGB combination with no L selected, and use each master to each channel. Then do an Auto STF, apply that to a Histogram Stretch, and that's pretty much it. I stopped there because I was just trying to show how to get rid of the dominant green for you.

Another way is to use Pixel Maths. By trial and error you'll find for this image that you need to combine the SII and OIII at 1x, but the Ha you really need to drop down to 0.1x. That is, the Ha is about 10 times as strong as the other channels.

Hope that made sense and helps?