Hi,
I am processing a rather nice data set (not my own) of the tarantula nebula. I want to use the lrgb data sets and nbaccent with the Ha AND Oiii files. Is that possible? It looks like I can only add one or the other under this option. I tried blending the 2 files and loading them but how would StarTools knows what's what. Thanks for the help!
Richard
NB Accent - multiple data
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Mike in Rancho
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Re: NB Accent - multiple data
Hi Richard,
Well if you have already blended them (as HOO, I presume?) just load that file in as the NBAccent, and pretend that what you have created is actually duoband data, so select the third option. When you finally get to the NBA module, there will be options for the hues involved as to both Ha and OIII, as well as the strength between Ha and OIII.
What I don't know, however, is if loading NBAccent and choosing duoband causes ST to make some assumptions about the dataset, such that it would deal with it in the normal "bicolor from OSC" fashion that might not perfectly apply to your blend.
But I think the differences would be rather minimal, so it would be worth just trying out what you already made anyway.
Well if you have already blended them (as HOO, I presume?) just load that file in as the NBAccent, and pretend that what you have created is actually duoband data, so select the third option. When you finally get to the NBA module, there will be options for the hues involved as to both Ha and OIII, as well as the strength between Ha and OIII.
What I don't know, however, is if loading NBAccent and choosing duoband causes ST to make some assumptions about the dataset, such that it would deal with it in the normal "bicolor from OSC" fashion that might not perfectly apply to your blend.
But I think the differences would be rather minimal, so it would be worth just trying out what you already made anyway.
Re: NB Accent - multiple data
Thanks Mike,
The blend is 50% Ha and 50% Oiii. I've tried adding this at nb accent at appropriate time, chose the 3rd option but no colour comes through. I can't imagine how StarTools could know what data is on there unless I assign it.
Ivo, is it possible to incorporate 2 nb accent files (or information from the 2 files)?
Cheers Richard
The blend is 50% Ha and 50% Oiii. I've tried adding this at nb accent at appropriate time, chose the 3rd option but no colour comes through. I can't imagine how StarTools could know what data is on there unless I assign it.
Ivo, is it possible to incorporate 2 nb accent files (or information from the 2 files)?
Cheers Richard
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Mike in Rancho
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Re: NB Accent - multiple data
Hi Richard,
Strange, I would think that should have worked.
Let's maybe get into more particulars of how you created your Ha-OIII blend. In order to make it comparable to duoband data, you want your Ha in the R channel, and OIII and the G and B channels. That way, as you say, ST knows what is in there, just like a duoband file.
I presume all your files are the same resolution and already registered. That will need to be the case. Using Compose, put your Ha file into R, and the OIII file into G and B. Choose RGB, RGB and keep. Save that file, it should be linear RGB and akin to a duoband stack.
I'd have to re-read the docs, there may be other methods of achieving this via Compose and other modules and I'm not sure which is best, if any. The thing you want to avoid though is saving the grayscale combined luminance only.
Anyway, then use that newly created file in the NB Accent slot with your other data.
I really think that ought to work if you try it, but I'm sure Ivo will have more clear instructions.
Strange, I would think that should have worked.
Let's maybe get into more particulars of how you created your Ha-OIII blend. In order to make it comparable to duoband data, you want your Ha in the R channel, and OIII and the G and B channels. That way, as you say, ST knows what is in there, just like a duoband file.
I presume all your files are the same resolution and already registered. That will need to be the case. Using Compose, put your Ha file into R, and the OIII file into G and B. Choose RGB, RGB and keep. Save that file, it should be linear RGB and akin to a duoband stack.
I'd have to re-read the docs, there may be other methods of achieving this via Compose and other modules and I'm not sure which is best, if any. The thing you want to avoid though is saving the grayscale combined luminance only.
Anyway, then use that newly created file in the NB Accent slot with your other data.
I really think that ought to work if you try it, but I'm sure Ivo will have more clear instructions.
Re: NB Accent - multiple data
Hi Mike,
What I did was blend 50/50 of the two stacks - Ha and Oiii on the linear level. I don't quite understand the logic behind it though. How would ST know which part of the image comprises of Ha and which Oiii? Thanks for all our help.
Richard
What I did was blend 50/50 of the two stacks - Ha and Oiii on the linear level. I don't quite understand the logic behind it though. How would ST know which part of the image comprises of Ha and which Oiii? Thanks for all our help.
Richard
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Mike in Rancho
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Re: NB Accent - multiple data
Hi Richard,
Were you using Layer to do that blend? If so then I think yes, blending two monos into another mono there would be no way to differentiate, absent some assignment to color channels.
I thought there would be an easy way to do this via Compose, and also adjust the exposure if needed, but either I confused myself or I totally forgot how to do it. At the moment I can't seem to get it out of grayscale mode such that a proper linear RGB can be saved. My apologies!
However, if you have Gimp it can be readily done in there, and even saved as a fits if that's the format you want. Just load your mono Ha and OIII into layers, then go to COLORS -> COMPONENTS -> COMPOSE. Then you can assign the layers to color channels as you choose. I would put the Ha into Red, and the OIII layer into both G and B. That's it, then save it.
https://docs.gimp.org/2.10/en/plug-in-compose.html
Now, if it's what you want to do, that file should be a faux duoband, which you can Compose into ST as the NB Accent by telling it such. That should open up the possibilities of balancing in both bands. I think!
Were you using Layer to do that blend? If so then I think yes, blending two monos into another mono there would be no way to differentiate, absent some assignment to color channels.
I thought there would be an easy way to do this via Compose, and also adjust the exposure if needed, but either I confused myself or I totally forgot how to do it. At the moment I can't seem to get it out of grayscale mode such that a proper linear RGB can be saved. My apologies!
However, if you have Gimp it can be readily done in there, and even saved as a fits if that's the format you want. Just load your mono Ha and OIII into layers, then go to COLORS -> COMPONENTS -> COMPOSE. Then you can assign the layers to color channels as you choose. I would put the Ha into Red, and the OIII layer into both G and B. That's it, then save it.
https://docs.gimp.org/2.10/en/plug-in-compose.html
Now, if it's what you want to do, that file should be a faux duoband, which you can Compose into ST as the NB Accent by telling it such. That should open up the possibilities of balancing in both bands. I think!
Re: NB Accent - multiple data
Hi Mike,
So sorry to reply to your most generous help this late. I wasn't successful following your advice and the link re: gimp. I'll try again the tell you my results maybe with screenshots. The data is from another version of Tarantula this time taken with hours perhaps days of exposure (challenge from Astroimiging Channel). I'm processing lrgb and accenting it with Ha and Oiii (maybe I already said that..)
Richard
So sorry to reply to your most generous help this late. I wasn't successful following your advice and the link re: gimp. I'll try again the tell you my results maybe with screenshots. The data is from another version of Tarantula this time taken with hours perhaps days of exposure (challenge from Astroimiging Channel). I'm processing lrgb and accenting it with Ha and Oiii (maybe I already said that..)
Richard
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Mike in Rancho
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- Joined: Sun Jun 20, 2021 10:05 pm
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Re: NB Accent - multiple data
Sorry Richard, I thought that should work. 
But in my continuing quest to keep tinkering with new things, I have a different option for you. Do you have or know your way around Siril at all?
You don't need to know how to stack or post-process in it (both of which I find confusing), as this is just doing a layer combine operation. But it helps to play with things a little to understand how Siril displays the data in the preview window, the R, G, B, and RGB tabs, and the various screen stretching options along the bottom.
What you would want to do is set your home file location where your data for this is (little house icon). Then under Image Processing to to RGB Compositing, which pops up a little window. There, you can load your Ha into the R, and your OIII into the G and B. You will see this on the screen (but you might need to change the screen stretch from linear to auto or histogram, and the tab to RGB). Your files should already be registered, I presume? If not they can be aligned in this window - though you will have to register again later against your LRGB data.
There are some options I don't really understand (HSV, CIELab) so I just left it be. In any event, after closing this composition you would now do a save as using the icon up on the top, give it a file name, and I would probably maintain 32-bit FITS.
That should give you a composited HOO linear file, that you can then pretend is from a duoband and use in NBAccent for both Ha and OIII accenting at the same time. Cross fingers!
You may or may not need to do a separate Wipe first and save it before compositing. Siril can sometimes be funny about the channel levels it seems to save things at (giving a bright cast or gray screen), though the data always seems to AutoDev just fine.
I hope it works!
But in my continuing quest to keep tinkering with new things, I have a different option for you. Do you have or know your way around Siril at all?
You don't need to know how to stack or post-process in it (both of which I find confusing), as this is just doing a layer combine operation. But it helps to play with things a little to understand how Siril displays the data in the preview window, the R, G, B, and RGB tabs, and the various screen stretching options along the bottom.
What you would want to do is set your home file location where your data for this is (little house icon). Then under Image Processing to to RGB Compositing, which pops up a little window. There, you can load your Ha into the R, and your OIII into the G and B. You will see this on the screen (but you might need to change the screen stretch from linear to auto or histogram, and the tab to RGB). Your files should already be registered, I presume? If not they can be aligned in this window - though you will have to register again later against your LRGB data.
There are some options I don't really understand (HSV, CIELab) so I just left it be. In any event, after closing this composition you would now do a save as using the icon up on the top, give it a file name, and I would probably maintain 32-bit FITS.
That should give you a composited HOO linear file, that you can then pretend is from a duoband and use in NBAccent for both Ha and OIII accenting at the same time. Cross fingers!
You may or may not need to do a separate Wipe first and save it before compositing. Siril can sometimes be funny about the channel levels it seems to save things at (giving a bright cast or gray screen), though the data always seems to AutoDev just fine.
I hope it works!
Re: NB Accent - multiple data
Hi Richard,
just 1 more idea to x-check: When You load Ha & O-III into COMPOSE, by default "Channel Interpolation is set to On. Have You ever tried to unselect it? I suppose Your Ha & O-III files are mono, so Channel interpolation was not needed. As Mike said, loading HA into R and O-II into G&B should result in an RGB color image. Saved as FITS, this should work like a single duoband file.
Clear Skies,
Jochen
just 1 more idea to x-check: When You load Ha & O-III into COMPOSE, by default "Channel Interpolation is set to On. Have You ever tried to unselect it? I suppose Your Ha & O-III files are mono, so Channel interpolation was not needed. As Mike said, loading HA into R and O-II into G&B should result in an RGB color image. Saved as FITS, this should work like a single duoband file.
Clear Skies,
Jochen
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Mike in Rancho
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Re: NB Accent - multiple data
Jochen I'm not sure either of those are going to work.
Channel interpolation options would not be available if all channel slots are filled, only if one is missing. Also I'm pretty sure we tried the compositing things way back at the start of Richard's questions. I don't think I was able to find a way to get it out of grayscale luminance mode and save a linear RGB file (HOO here) with actual colors.
Maybe I'm just not being creative enough to find a way for ST to (in effect) put together RGB compositing from mono files - at least for file operation purposes and not to continue through with actual post-processing. Hence the experiments with Gimp, Siril. I also checked ASTAP but was unable to find a similar function (except classify by filter but that doesn't quite work).
Channel interpolation options would not be available if all channel slots are filled, only if one is missing. Also I'm pretty sure we tried the compositing things way back at the start of Richard's questions. I don't think I was able to find a way to get it out of grayscale luminance mode and save a linear RGB file (HOO here) with actual colors.
Maybe I'm just not being creative enough to find a way for ST to (in effect) put together RGB compositing from mono files - at least for file operation purposes and not to continue through with actual post-processing. Hence the experiments with Gimp, Siril. I also checked ASTAP but was unable to find a similar function (except classify by filter but that doesn't quite work).