RGB Combine tool and pixel math question

Here is an screenshot trying to implement the above settings but I don't know if I'm doing it right. You will see my settings on the left and the right. Also notice how the edge of the Ha image is bleaching through. Is this normal given my settings?

https://photos.app.goo.gl/scuxoqpxWhBfecvR6

Best,

Miquel

That looks like you're doing it right yes. To have that edge there is because the frames don't line up and basically the data is different at these non overlapping places, giving different appearances.

Hi Vincent,

Thanks for the validation.

I used the below Ha integration and Color integration:

Neil's image: ?dl=0

I'd be happy to give that a try, but then I need some of your calibration files and raw data frames. You can upload those to the following address: AstroPixelProcessor upload and login using appuser as name and password. Maybe make a directory first with your name on it.

Hi @vincent-mod

The Ha image and Color image were already calibrated and integrated using APP, so Neil produced the above processed image just with the Ha and Color images that I just attached above.  He did not use the raw frames, but I will be happy to give it a shot and see if I can upload everything in one location for you.

Thanks for giving it a try,

Miquel

Hi @vincent-mod again,

Here you have the information that you asked about. It will come in 2 sets, one set for the QHY9M CCD camera, which is the mono camera I used to capture the Ha signal, and then another set for the QHY8L, and this one is color signal.

QHY9M (Mono CCD for Ha signal):

Master Bias: https://www.dropbox.com/s/pl12p82g3b0bodo/MB-ISO_QHY9_CCD_gain_0.0-exp_0.01s-30subs-Camera.-3336x2496-NR-avg.fits?dl=0

Master Dark: https://www.dropbox.com/s/1xte9aeosj2av7c/MD-ISO_QHY9_CCD_gain_0.0-exp_300.0s-30subs-Camera.-3336x2496-NR-avg.fits?dl=0

Master Flat: https://www.dropbox.com/s/8weha99b6iuqed0/MF-ISO_QHY9_CCD_gain_0.0-exp_13.98s-30subs-Camera.-3336x2496-NR-noBl-avg.fits?dl=0

Ha Lights: https://www.dropbox.com/s/crwzbcehptk400e/QHY9M_Ha_Lights_IC1318_ha.zip?dl=0

QHY8L (OSC CCD for Color signal):

Master Bias: https://www.dropbox.com/s/cu8xgc10jrgzgi1/MB-ISO_QHY8L_gain_0.5-exp_0.04s-30subs-StarSenseSci-3328x2030-NR-avg.fits?dl=0

Master Dark: https://www.dropbox.com/s/8aidljw2yof79j4/MD-ISO_QHY8L_gain_0.5-exp_120.0s-30subs-StarSenseSci-3328x2030-NR-avg.fits?dl=0

Master Flat: https://www.dropbox.com/s/xxgzwtjlzqyobyy/MF-ISO_QHY8L_gain_0.5-exp_2.11s-30subs-StarSenseSci-3328x2030-NR-noBl-avg.fits?dl=0

Color Lights: https://www.dropbox.com/s/10sfa3tiwg9vdr4/QHY8L_Lights_IC1318.zip?dl=0

Look forward to learn some good stuff from you. Good luck with the processing.

Clear skies!

Thanks for the data! I will try to get it all downloaded and see if I can get something nice. I do have a busy schedule the coming week so it may be delayed a week unfortunately.

ps. I think it's better to save the raw frames and not the fits done by SGP, or are these camera's doing fits themselves?

So, in the end it turned out to be a bit difficult with the fits files, so I went back to the two integrations. This is my attempt at it. As you can see, mine has less blue. The problem with these type of questions is that it all comes down to personal preference. I like mine in the sense it's less harsh so to say and I trust the color calibration tool a bit more above my own taste. So to me, this data has a bit less color but to get that out requires a lot of (in my opinion) destructive stretching. More data (like luminance and shorter RGB exposures to get the star colors in the center of them) would allow you to do that in a nicer way, hence why I tend to not overdo it. But that's my opinion, you may very well still want another look, I however never pushed APP's settings too much so that will either require more experimentation or the use of something like Photoshop. I can see he used quite a bit of, probably, special tools and filters to get the blue around the stars a bit nicer. Maybe nice to know a little bit about his exact procedure?

Hi @vincent-mod,

When I worked with my Canon 40D from Hutech, I get raw format, but when I worked with my temperature regulated CCD's, I get fits format. As far as I know, there is no loss of quality between what you would consider RAW in DSRL and FITS in CCD.

Best,

Miquel

Hi @vincent-mod,

Thanks for giving my processing a try. I would interested to know how you got rid off the edge I was seeing on my processing.

I now have both of your images (Neil's image with Photoshop and your image with APP) in the same monitor, so there is no monitor calibration issues by having them in 2 different monitors.

You're correct, I see a noticeable lack of blue in processing and the blue stars, instead of having a nice blue halo around them, they seem to have a blue highlight between 4p-6pm.

What I like about your APP processing: I like your RED rendition and I like the fact, that it is less noisy.

What I like about Neil's APP processing: I like the color balance across all the spectrum and I like that he was able to achieve a higher level of contracts between the the more diffuse nebulose details and the most prominent nebulose details, which give his rendition a less flattish and more 3D effect.

As you said, and I totally believe that,  it's a question of taste.

Best,

Miquel

Posted by: @mcbbcn

You're correct, I see a noticeable lack of blue in processing and the blue stars, instead of having a nice blue halo around them, they seem to have a blue highlight between 4p-6pm.

Indeed, it seems to be part of your data, but somehow Neil used a post-processing feature that made it nicer all around. Would be nice to know how he did that.

What I like about your APP processing: I like your RED rendition and I like the fact, that it is less noisy.

What I like about Neil's APP processing: I like the color balance across all the spectrum and I like that he was able to achieve a higher level of contracts between the the more diffuse nebulose details and the most prominent nebulose details, which give his rendition a less flattish and more 3D effect.

Yes he definitely has brought out the colors, but again I would be interested to know if this was done using masks and features like that. In those aspects APP is still lacking, so for some special needs it's still nice to be able to use various software packages. This will be addressed though in future versions.

As to not having an edge, in this example I only replaced the red channel with the Ha data, maybe adding that signal to all channels causes an artefact?

Hi @vincent-mod,

I just contacted Neil and sent him the link to our post and if he has time, I asked him to drop by and see if he can share a few thoughts. I cross my fingers that he can do it, as having folks like you and him exchanging thoughts and ideas, it is a great opportunity for me and folks who don't know as much to learn from the experts.

Best,

Miquel

That would be great, I'm not considering myself an expert though. 🙂 When it comes to deep post-processing I lack a bit of knowledge, I always used PixInsight and got quite far with that, that still has some nice post processing tools I could use on your image to get closer. Just haven't the time at the moment unfortunately.

Hey @vincent-mod,

Well, when I look at my processing and your processing, I feel like you are more than an expert than I am. 🙂

I think Neil also has some pixinsight experience, but I don't remember. Anyway, it will be good if we can get his (and yours) bits of wisdom for people like me who are running behind people like and him with more experience. I appreciate again you giving it a shot, as I know these things take time. 😎 

Hi @neilh

It's nice to see you here and thank you for sharing the detail explanation of your processing. I look forward to hear the thoughts from Vincent and see if he thinks we can do any of these steps with APP.

Best,

Miquel

Very nice of you Neil to drop by! First I'll reprocess this one with the 80-20-20 mix to see if I can get that to work nicely. Thanks again for the info!

10 min later: Ok, so that mixing did the trick in getting the blue better all around. The big star in front did still loose color after color calibration, overall calibration does look good so I'm wondering what to make of that. I did all steps in APP and I think I'm getting a bit closer to Neil's result. It is more noisy, but that simply a fact of life when you want to get that brownish stuff to get out as well, more data is the only remedy for that. Using APP's sharpening I think I got the details out of the nebula a bit better.

If you're happy with this result Miquel (and credits to Neil for the mixing idea) I can tell you the steps I took.
ps. right-click and open in a new tab gives you the full resolution

Hi @vincent-mod,

Thanks for giving it another shot. It is starting to have less of flattish look and the stars rendered nicer with full halos around them. Also, the blue is starting to pop-out a bit more. Overall, I like it.  Yes, please, share your workflow steps and thanks for your help,

Best,

Miquel

Hi Neil,

I love your last rendition of the image. It's fantastic. Thanks for sharing your process.

Best,

Miquel

@neilh

Yeah, it lost that blue halo right after me color calibrating the result. According to the graphs, that calibration seems pretty spot on, so I'm now wondering if the emission of that star is less blue than the others? If that makes sense that is, I'm not a astrophysicist. 😉 I'll try another attempt with some extra processing of the separate integrations. Will take a bit as I'm moving to another holiday home at the moment.

Thanks a lot for the sharing of your attempts!

@mcbbcn

My steps were as follows;

1. Registering the two integrations and saving the resulting registered frames.
2. RGBCombine, where I did the 80-20-20 trick in my latest result
3. In the tools(9) tab I selected "Batch Modify", APP then asks if you want to modify the image which is open in the image viewer. I then draw a box around the area with overlap of both integrations (where they don't overlap, you get that edge which is unavoidable as the frames were not aligned during you taking the picture).
4. I select "Crop ok" on the lower left side and the crop is made.
5. "Calibrate star colors", I select a few areas, usually outside too much nebulosity and go for calibration. You get graphs telling you the before- and after spreads in the various color channels, they should fall close to the predicted model (which is the green line).
6. HSL selective color, I basically did what Neil mentioned in his steps of getting some of the various colours out of their respective channel. It doesn't have a huge effect, not sure why as I never used this tool too much (@mabula-admin ?).
7. I start manipulating the image, I turn saturation on and give a some decent value like 0.35, I then turn the Sat. TH (saturation threshold) down a notch, until I see the background getting saturated which you don't want, so just around the value it doesn't I set that.
8. I up the contrast a bit (CON in the slider) and turn up the sharpening (SHARP). This doesn't affect the stars as they are mostly protected automatically, but can bring out the details in the nebula nicely as you can see if you look at 100% on my latest attempt. The swirls and such are nicely defined.
9. Save.

I think Neil also added some denoise to the mix? I personally tend to not do that (which is where differences in results come from for instance), I just accept the noise as part of the game. 😉 Maybe in the future APP might get a nice one, usually they tend to make details go away a bit.

Hi @vincent-mod,  

Thanks for sharing your steps, and I agree with you, perhaps @mabula-Admin can share his thoughts too.

Best,

Miquel