How to develop an H...
 
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How to develop an H-alpha enhanced Luminosity channel in APP  

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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
03/07/2019 11:45 am  

Hi, 

I am in an entry-level of multichannel monochrome imaging. Usually, the RGB combine tool works fine for most when data per each channel are good. I used to adjust weight for different signal intensity in the RGB combine tool. However, it was very hard to produce the best result when all channel were adjusted altogether. It would be nice to have decent monochrome hybrids prior to combine them, such as H-alpha enhanced Luminance , or OIII enhanced Blue. Is it possible to do so in APP?

Regards,

Kijja

This topic was modified 4 weeks ago by Vincent Groenewold - Moderator

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(@vincent-mod)
Galaxy Moderator
Joined: 2 years ago
Posts: 596
04/07/2019 7:09 pm  

So I don't have APP at the moment standing-by, but isn't it possible to make these combinations with the combine tool? For instance by assigning the various lights to the channels you're interested in.. not 100% sure if that's your intention.


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(@mestutters)
Red Giant Customer
Joined: 2 years ago
Posts: 58
04/07/2019 11:03 pm  

Hi Kijja,

I think you can achieve what you want quite simply though I do not know whether it will greatly help when you get to RGB Combine.

If you look at TAB  6)  Integrate,  under Multi Channel / Filter options,  there are three options available on the selection list:  Integrate per Channel, per All,  and per Channel and All.

I use the Per Channel and All option when I am doing an LRGB integration.  It provides me with separate LRGB channels and also a Super Luminance Channel that combines the lot.

For what you want to achieve I would load all my LRGBHa and OIII and process them through to Integrate.  I would then Integrate first using the per Channel option.   I guess from your original question you have already  already done something similar to this in order to get to RGB Combine.  

Having done the above I would then:

a)  For an Ha enhanced  Luminance I would then deselect (but not delete) all but the  Ha and L subs from the file list  then integrate just these subs these using the Integrate All option.

b)  If I wanted an Ha enhance R, I would select only the Ha and R subs and Integrate All with just these.

c)  Similarly for Oiii and Blue select only these subs then Integrate All with just these.

Obviously for all this to work you must have opted for Multi-Channel / Filter Processing at Tab 1) Load.

By only selecting / deselecting subs from the file list (rather than deleting) you will preserve all the registration and normalisation data built up when the subs were first processed.

If you try this approach I would be interested to hear if it helped you any at RGB Combine.

Best of Luck

Mike

This post was modified 2 months ago by mestutters

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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
05/07/2019 3:37 am  

Thank you Mike your approach  sounds straightforward  I am sure to try it. Can we adjust NB intensity in an enchanted channel?

Clear skies 

Kijja


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(@mestutters)
Red Giant Customer
Joined: 2 years ago
Posts: 58
05/07/2019 10:17 am  

Hi,

My thoughts for what they may be worth.

I can't recall seeing anything from Mabula about doing what I've suggested so I guess we are thinking out of the box here.

I've included Ha subs within Luminance / Super Luminance using Integrate All in a small number of targets and was satisfied with the eventual result. 

Like you I found blending narrowband (Ha only as I don't currently have an OIII filter)  with broadband and found it difficult to do.  And even when I achieved a result in RGB Combine that looked promising the image would often change dramatically during Calibrate Star Colours which was disheartening to say the least.

When you ask 'Can we adjust NB intensity in an enchanted channel?', I would say that you can adjust the contribution of the blended channel to the final image using the features of RGB Combine but I think there is nothing available during Integrate other than to select a percentage of the available NB subs selected.

Interested to hear how you get on but my approach for now is to blend my NB into the Luminance  as I described so as to incorporate the greater detail and contrast available in NB  into the final image, then to adjust the overall colour balance using only the RGB channnels during RGB Combine.  Maybe a very small contribution from NB could be added to the colour channels at this stage so as to enhance detail but minimising subsequent problems  during CSC from overwhelming the main RGB inputs.

Regards

Mike

 


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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
05/07/2019 11:17 am  

Hi,

Thank you Mike. I’ve tried adjusting proportions of Ha assigned to both R and L  together with LRGB It’s difficult to avoid negative effects of NB on color balance. Layers blending in APP? 

Regards

Kijja


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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
05/07/2019 4:38 pm  

Hi, all

Here is my Ring Nebula in LRGB with Ha OIII enhanced.

combine RGB image 5 lpc cbg St

 


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(@mestutters)
Red Giant Customer
Joined: 2 years ago
Posts: 58
06/07/2019 9:26 am  

Hi Kijja,

I've not tried imaging M57 myself but I think it is a quite difficult target - rather small and having a tremendous brightness range.  

I like the colour balance of your stars and if I look closely I do see a faint hints of colour in the outer fringes of M57.  I like also that IC1296 is visible.

How much time have you spent so far and how did you finally do the RGB Combine?

I think there is a perfectionist  lurking in you so I think you will be spending more time and effort on this one!

Mike


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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
08/07/2019 1:00 am  

Hi Mike,

Thank you for your kind words. I took this image in one night, approximately 40 minutes in each filter (L R G B Ha OIII). The final image was combined in RGB combine tool in one step as  : L = 100%L, R = 100%R, G=100%G, B=100%B, Ha = 20%L &20%R, OIII= 30%G &40%B. I've tried your method of processing Ha with L and R separately, but I could not see any differences between the two methods.

You are right about this object. Most of my subs are over exposed. I think more subs in NB will probably makes the peripheral fringe pop-up. However, it is now in the midst of Monsoon season in my country. Next month will be a better time for astro-imaging again.

Clear skies,

Kijja


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(@pete_xl)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 8
15/07/2019 2:13 pm  

In my understanding on what is happening in the outlier rejection process ist can not be a good idea to integrate data of different sources (filters) into each other. This is like mixing apples and pears. If for instance you have signal (structure) in the data of one source that is not or less present in the data of another source it should be degraded in the outlier rejection process while stacking.

Also mixing different sources leads to inconsistent star count, fhwm and "quality" values and the integrity of the stacking weights for quality (which is best to choose) in an integration should suffer from that.

In my experience it is better to produce a clean stack for each filter and assign the weights to the R/G/B channels in the combine tool.

 


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(@kijja)
Red Giant Customer
Joined: 2 years ago
Posts: 67
18/07/2019 4:31 am  

@pete_xl

Thank you Peter. Your approach sounds logical to me. There are some differences when combining channels in APP and Photoshop. Photoshop has a powerful tool in layer  (including layer mask) , which layer's opacities can be adjusted and we can view results immediately. I'd love to has some of such features in APP post-processing tools.

Clear skies,

Kijja


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