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Droogie 2001

NGC7822 - Cedarblad

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Whilst waiting for the California Nebula to rise to a decent altitude I thought I would try out NGC7822.
This is a 6 hour Hydrogen Alpha image. I would like to add some O3 to the image but will have to see if the weather allows this. Please click the image as the preview loses a lot of detail..

Scope: William Optics Star 71
Mount: Celestron AVX
Camera: Moravian G2-8300 – Mono
Filter: Chroma Ha 3nm
14x1500s exposures (6 hours) at -30c
Total 6 hours.
Flats & BIAS

Processed in PixInsight

 

NGC7822 - Cedarblad - Final.png

Revised 14.10.18 - Brighten Core

 

drizzle_integration_DBE_working_completed_PI_rework.png

Edited by Droogie 2001
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That's a nice image!  I love how Ha can produce mono images.  You will not regret adding OIII--but don't stop there.  Add SII and you will be even more satisfied.  The entire region takes on a 3D appearance.  It always amazes me that areas that seem to be adjacent to other areas in the mono image are actually far behind, or in front of the area.  Adding the other channels brings this out

Rodd

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Thanks Rodd. Yes the mono look can really bring out the detail. Still would like to add more Ha but at least with O3 I can produce a colour version. I will get an SII filter at some point but the Chroma 3nm are £485 and having barely had chance to get O3 it will have to wait a while.

 

 

 

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How impressive! I particularly like the center of the image - processing is superb.

David

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Hey Droogie.

A great image!!!

If i would allow myself one comment: I think you overdid the HDRMultiscaleTransform a little. It seems like you don't have any 'bright' small areas anymore, just a patches of similar brightness and it reduces the depth of the image in my opinion. (i see this a lot if i go too far with my own images and HDRMT).  In most cases i will blend this kind of result with the original image or a lesser-'flattened' one to leave certain highlights i desire to keep the depth.

Just a thought and personal opinion and hopefully not an imposition on your creativity!

Kind regards, Graem

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Hi Graem,

Thanks for the comments. No problem with pointing out suggestions and I really appreciate the feedback. I agree with you that I have over done the HDR. The original output was very bright with little detail and so was aiming to reveal the columns / pillars of gas located within the nebula, the end result does however lack depth. I did ponder this at the time as I really wanted to obtain that detail, looks like I went too far.
I will see if I can edit it to a better result or come back to this when I have obtained some O3.

Thanks you everyone's comments.


 

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Couldn't resist having a quick go! (Added to my first post) Not much brighter but if I push it too far it becomes too apparent.
Anyway I will consider the effects of HDR more scrupulously in the future. 

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5 hours ago, Droogie 2001 said:

Hi Graem,

Thanks for the comments. No problem with pointing out suggestions and I really appreciate the feedback. I agree with you that I have over done the HDR. The original output was very bright with little detail and so was aiming to reveal the columns / pillars of gas located within the nebula, the end result does however lack depth. I did ponder this at the time as I really wanted to obtain that detail, looks like I went too far.
I will see if I can edit it to a better result or come back to this when I have obtained some O3.

Thanks you everyone's comments.


 

I don't know if you're only using PI to process your image, but a revolution happened when i started using PI only for certain tasks, and putting everything together (with dozens of layers and masks) in Photoshop. It was a gamechanger, and allowed me to process whole images with a certain effect (for example HDR) but then only apply a part of the image to the resulting image, giving me massive control.

In this case, i'd want HDR of the core with a small number of layers, and the outskirts with higher number, and then combine it by hand (seriously 'brushing' the areas into visibility) - but probably even turn to LHE (Local Histogram Equalization) to pull out small scale contrast of the pillars.

PI is very scientific and mathematic and absolutely excels at many tasks, but not in layering, masking and doing lots of the things that one wants to do when making an artistic picture, versus a scientific image... Just my opinion!

Kind regards, Graem

Edited by graemlourens

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Thanks again Graem.

I do some final work in PS and occasionally drop back into PI though I realise I am out of the XSIF file format. 

My skills in PS are limited so what you describe is daunting but certainly makes senses.  Will start off with basics and work from there.

Out of interest what file format do you use in PS. If I use TIFF then the image brightens up considerably so I use PNG.  

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3 hours ago, Droogie 2001 said:

Thanks again Graem.

I do some final work in PS and occasionally drop back into PI though I realise I am out of the XSIF file format. 

My skills in PS are limited so what you describe is daunting but certainly makes senses.  Will start off with basics and work from there.

Out of interest what file format do you use in PS. If I use TIFF then the image brightens up considerably so I use PNG.  

I always use TIFF, 16 Bit. And yes: The image will in many cases look brighter in Photoshop than in Pixinsight, but as far as i have seen and my research goes this has to do with the color profile (color profiles seem to be what determines how bright etc certain aspect of the image are on the screen, but do not alter the underlying data). This is also the reason why every screen will probably show the image slightly differently (more saturation / less, brighter or darker etc). This is also the reason why just directly printing the image to a printer mostly results in an undesirable balance of colors and brightness, as you will have to adapt the profile to match the depth the printer is able to produce etc (here i do not have much experience, and let professionals handle it)

PNG and JPEG are algorithms to reduce size (compressing and in the process loosing valuable data), and are not appropriate to transfer 'raw' data that is still in processing - they are rather used to share the final image, but you should not in any process go to PNG/JPEG and then come back as you will loose information. TIFF is a compressionless format without data-loss and that is also the reason why images are so gigantic compared to exporting the image to PNG/JPG/JPEG.

Based on my experience there is no advantage of staying in XISF / FITS format for the image in progress. These formats contain Location data, Filter settings, Binning etc, but after you have combined and stacked subs, this is not a relevant information - or if you really need it, can easily be added again at a later stage.

You can easily do an example: Export TIFF 16 BIT from Pixinsight. Open it in Photoshop, change some slight thing (can just be a simple green arrow somewhere) and open it in Pixinsight again - you will see that the brightness of both images is the same, this is due to that PI & PS interpret the data in different ways (or better said: have different output profiles active) but the underlying data is identical.

Kind regards, Graem

 

Edited by graemlourens

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4 hours ago, graemlourens said:

I don't know if you're only using PI to process your image, but a revolution happened when i started using PI only for certain tasks, and putting everything together (with dozens of layers and masks) in Photoshop. It was a gamechanger, and allowed me to process whole images with a certain effect (for example HDR) but then only apply a part of the image to the resulting image, giving me massive control.

In this case, i'd want HDR of the core with a small number of layers, and the outskirts with higher number, and then combine it by hand (seriously 'brushing' the areas into visibility) - but probably even turn to LHE (Local Histogram Equalization) to pull out small scale contrast of the pillars.

PI is very scientific and mathematic and absolutely excels at many tasks, but not in layering, masking and doing lots of the things that one wants to do when making an artistic picture, versus a scientific image... Just my opinion!

Kind regards, Graem

Very well put Graem! Exactly my thoughts about it. There are some great procedures in PI that I slowly lerned to use (and I am steadily learning more) but only to later import the result to PS for selective use with masks. I find using both programs this way is optimal. My problem with PI is that there are too many settings to consider and then you have to wait and wait and wait for the result. PS is much more direct where you immedeately see what is happening to the image, often aided by sliders. But clearly PI can do a few things that PS cannot.

So, Droogie 2001 you should go for the best of these two (very different) worlds by using them both.

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Lovely detailed image, you could get lost in it.  Mono is poetry but some colour will make your image sing!

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