PixInsight Forum

PixInsight => Image Processing Challenges => Topic started by: Josh Lake on 2012 March 04 07:00:12

Title: Narrowband Rosette Nebula
Post by: Josh Lake on 2012 March 04 07:00:12
To kick things off, I uploaded three frames of my first data with narrowband filters that I purchased this winter. I've processed it twice and am happy with the results, but I still have a lot to learn (in both acquisition and processing) and want to see what the pros can do with it.

Each master was integrated from 4 x 10 minute subs. Acquired with an SBIG STL-11000 with a Takahashi FSQ-106ED.

If you have signed up for the PixInsight Files AJAX server, here is the link to the folder (http://pixinsight.org/files/?repository_id=my-files&folder=%2F2011NarrowbandRosette).

My final full scale JPG of my second processing attempt (http://pixinsight.org/files/index.php?get_action=open_file&repository_id=1&file=%2F2011NarrowbandRosette%2FRosette-HSHO-Lake.jpg)

I used PixelMath to make a slightly modified SHO combination with a little H-alpha in each channel:
R = S*.9 + H*.1
G = H
O = O*.9 + H*.1

Then I used the H data as the Luminance frame to make a final HSHO image.

This was my first time really using Local Histogram Equalization (thanks, Harry!) and using Curves Transformation to make it a fully PI-processed image instead of tweaking in Photoshop.
Title: Re: Narrowband Rosette Nebula
Post by: Juan Conejero on 2012 March 04 08:44:02
Hi Josh,

Thanks for posting this nice image! I can't see your files on PF. Have you shared the folder (by clicking the Share button)?

Sorry, I should have included this in the welcome post, or better, I'll write a sticky post with instructions to post raw data.
Title: Re: Narrowband Rosette Nebula
Post by: Josh Lake on 2012 March 04 09:45:09
When I hit 'Share', I just get a list of specific users. If I leave it blank, is it publicly shared? I'm fine with doing that...

Edit: I shared you in explicitly, but I'm not able to select more people on the list. I also changed permissions to Read access for All and Group. Happy to keep trying things in order to find out how best to share...
Title: Re: Narrowband Rosette Nebula
Post by: Juan Conejero on 2012 March 04 12:41:53
Hi Josh,

I am having a hard time trying to configure ajaxplorer to facilitate sharing files among all users (I can't believe that one has to authorize each user explicitly...). While I try to solve this issue, I have copied your files to the following folder:

Forum Shared Files/2011_narrowband_rosette.jlake

Since all users have access to 'Forum Shared Files' there should be no problems. Sorry for the inconvenience.
Title: Re: Narrowband Rosette Nebula
Post by: Josh Lake on 2012 March 04 12:51:06
No worries, all in the course of making a new system work. A general shared folder is a good idea anyhow, and that's what I intended for my data.
Title: Re: Narrowband Rosette Nebula
Post by: Alejandro Tombolini on 2012 March 04 21:44:53
Hi, here is my attempt.

This is the first image that I process with narrow-band filters, so I had many doubts.

I gathered channels just like Josh but with the following weights:

R = S
G = H
B = O

To begin It was complicated with the DBE, It was almost impossible to eliminate red gradient. As you will see I applied a lot of times...

I have no clear how to manage colors. Is need the CC routine?, is not? So the process went as a normal RGB image and got this.

The final image and processes are in the repository. (I tried to upload the image in the same folder but could not, I did another).

Regards, Alejandro.

http://endor.uv.es//data/public/48a171d4989cf07f95624ef9a1671a52.php?lang=en
Title: Re: Narrowband Rosette Nebula
Post by: Raymond on 2012 March 05 13:32:42
Hi
here is also my processing attempt of the Rosette. The image and the processing descriptions are in the Forum Shared Files section under '2011_narrowband_rosette_rkneip'.
I'm using Pixinsight for more than a year, so any comments on how to improve are welcome!
Thanks
Title: Re: Narrowband Rosette Nebula
Post by: Josh Lake on 2012 March 05 17:32:20
Nice! What led you to that particular color palette? Was it a conscious choice or did you intentionally 'go for' that? Either way, it's a striking take on the data.
Title: Re: Narrowband Rosette Nebula
Post by: Raymond on 2012 March 06 13:18:27
The reason for choosing this color palette was that I 'wanted' a red (or something similar) emission nebula. The mixing of the channels was only for fun.
Anyway, the original data are of an excellent quality; a lot of small structures are visible in the nebula and the image has a rather low noise level.
Title: Re: Narrowband Rosette Nebula
Post by: Lex on 2012 April 25 12:29:56
Hi all,

it is the second time today that I give a try downloading files from the PI server without success; is it down maybe?

thanks
Title: Re: Narrowband Rosette Nebula
Post by: Alejandro Tombolini on 2012 April 25 13:26:53
Hi Lex, try this links:

http://endor.uv.es//data/public/100514640dc484c450d92f9d3a07b0f7.php?lang=en
http://endor.uv.es//data/public/99b5cb7b3a04c549da8bfc1b2ae5348f.php?lang=en
http://endor.uv.es//data/public/59494ce99906c625077c72d5fc5eb4d5.php?lang=en

Regards, Alejandro.

Edit:  :-\ mmmhh, you are right, some thing is wrong
Title: Re: Narrowband Rosette Nebula
Post by: Josh Lake on 2012 April 25 13:49:53
What's going wrong? Do I need to re-upload it? This file set was from the original PI Files site, pre-Endor. I can push this up to Endor if need be, let me know.
Title: Re: Narrowband Rosette Nebula
Post by: Alejandro Tombolini on 2012 April 25 13:55:53
Files are in endor, I can see them and download, but the link generated to shere seems not to work.

Saludos. Alejandro.
Title: Re: Narrowband Rosette Nebula
Post by: Lex on 2012 April 25 14:25:36
Okay, perhaps I am doing something wrong --> Have I got to wait to receive the Sign Up parameters of the PI team or does it work without account?
Kind of confused about this  ???
Title: Re: Narrowband Rosette Nebula
Post by: TeeJay on 2012 April 26 09:21:21
Hi Josh,

here is my attempt. I used a self-modified tone mapping procedure based on J-P Metsavainio. 100% PI processing. 100%-Version (http://www.teejay.ch/forum/NGC2237_hubble.jpg)

All images {
 1. Crop
 2. DBE
 3. HistogramTransformation
 4. Copy and rename to "starless_"
 5. Starremoval with Starmask and MorpohlogicalTransformation
 6. GREYCstoration
 7. CurvesTransformation(a little bit HDRMT for the H-alpha)
}
8. LRGBCombination (R=starless_[SII], G=starless_H-a, B=starless_[OIII])
9. Extract Luminance
10. Pixelmath (extracted_L*2+Rosette_Ha+Rosette_OIII+Rosette_SII*1.2) <-- the HistogrammTransformed images, not the starless
11. CurvesTransformation of the new Luminance
12. LRGBCombination (L=new_L, play a little with the Channel Weights, play a little with the Transfer Functions, use Chrominance Noise Reduction)
13. CurvesTransformationwith Starmask (a little darker, chrominance and saturation to zero!)
14. UnsharpMask with inverted Starmask
15. DarkStructure Enhancement
16. Finale CurvesTransformation

<1h of work...

That’s it!  In fact, if this would be my own image, I have been done a deconvolution and played a lot more with the parameters, so the processing time would be at last 4h...

I know this is not a scientific method, but it’s very good for pretty pictures and this is actually art. 

CS TeeJay

Edit: As you can see my image have a more softer/European-style look with more focus on the faint outer nebula, in fact I am from Switzerland so this is okay.  But if you like the American-style look you can perform a HDRMT and push the contrasts at the end.