[Solved] Using the Hubble pallette and the HSL tool

@msamazing When integrating the lights you should not assign them to any filter at all. APP should be able to recognize the filter from the FITS headers of the images and will assign Ha, OIII or SII to them. When done integrating you can choose SHO (Hubble) 1 or 2 to create an RGB image.

@wvreeven Thank you very much!  I assigned them to the color channels thinking that was what I was supposed to do.  I will start over and try again.  I really appreciate your help!

@wvreeven- problem #2.  I ran the Hubble option and the colors are wrong.  It came out green.  What did I do wrong here?  I just took a photo of my screen to show you.

@msamazing You did nothing wrong. The Hubble palette assigns Ha to green and between Ha, OIII and SII, Ha is the strongest. So this is perfectly normal. Next you need to tweak the colors so it shows more the golden orange of the Hubble palette that we all love so much.

How do the colors look when you use SHO (Hubble) 2?

@wvreeven - LOL.  Do you know if there is a tutorial on where I go from here?  I am not sure how to do that.  Is it something I can do in APP or do I need to go to a different app like Photoshop?  Is there something that you know which can help me with this?

@msamazing It is possible to do with APP via HSL Selective Color in the Tools tab. Unfortunately there is no tutorial for that yet. I'll ask Mabula if he can give some pointers. You could export the image to TIFF in APP and then load it in an external tool to process it further there.

Hi Michael @msamazing,

Making a Hubble palette completely in APP is perfectly possible and easy these days. Soon I will make a video tutorial on how to do just that 🙂

But I will try to help you to get the most out of your narrowband data 😉

First, are you using APP 1.083 the new release? If not, please update, because it has much better tools for exactly this purpose.

If you load your lights to make the integration, you simply need to use the proper filter names. If you shoot with a H-alpha filter, you need to use that, like Wouter already explained.

Then when you have your 3 integrations, H-alpha, SII, OIII, you load them into the RGB Combine Tool, making sure that the integrations are correctly recognized as H-alpha, SII, OIII  and load them while setting the SHO1 or SHO2 formula. SHO means that SII is mapped to Red, H-a to Green and OIII to blue.

Normally, an initial SHO1 will look rather green with purple stars like this, so your result is not odd at all:

Using SHO2, set the formula to SHO2 and click on new formula (this applies that formula) and then recalculate. SHO2 will already reduce the green cast and purple stars:

The formula shows that the channels are being mixed a bit, which has the effect that the green and magenta casts are reduced.

Now, per object and per dataset, there is no fixed formula that will always work because it all depends on the object and the quality of your data which formula will give you the most pleasing result. So you need to tweak the formula to get even nicer results, I made a custom formula on this by mixing the channels a bit differently when compared to SHO2 formula:

Notice that I also increased the multipliers for SII and O3, that really helps, because otherwise the strong H-alpha signal overpowers SII and O3. This now already looks like a good Hubble palette, right?

Next you can play with the formula even more... realise that H-alpha has the best signal and contrast. Why not use that to make up most of the Luminance of the composite?

I set the L slider for H-alpha to 75%, so that means that the H-alpha signal contributes 75% for the luminance of the composite. That reduced noise and increases contrast, because H-alpha has better contrast and less noise when compared to OIII and SII.

Further tweaks can be done with HSL Selective Color, leading to

this for example. The HSL Selective Color tool enable you to tweak all colors in the image to your liking and you can tweak low lights or only the bright stars.

I think for now, let's us try to first get the Composite result much better with the RGB Combine Tool using my formula examples as shown above 😉 Then afterwards I can help you with the HSL Selective Color tool.

Mabula

Hi Michael @msamazing,

Can you please upload your data here:

https://upload.astropixelprocessor.com/

use username and password: upload

And let me know once uploaded 😉 I will check it as soon as possible.

(I can not open your dropbox link since dropbox is forcing me to register with them, which I don't want to do.)

@mabula-admin - this doesn't work.  It doesn't recognize my sign in and it won't allow me to change the password or set it up.  

@msamazing As Mabula wrote, you need to use upload both for username and password. Your APP credentials won't work. 

@wvreeven got it now.  Thank you.  I thought he meant that there was a different password and user name for when you upload.

I am not sure if I did it correctly .  Here is a screen shot of my 3 uploaded files.

Hi Michael @msamazing,

Thanks, the upload was fine 😉 I will be looking at it right now, will report back soon with my findings.

Posted by: @msamazing

@wvreeven- problem #2.  I ran the Hubble option and the colors are wrong.  It came out green.  What did I do wrong here?  I just took a photo of my screen to show you.

 

Hi Michael,

So this is not wrong but perfecly normal with the most simple Hubble palette SHO1 formula. I get exactly the same and your individual SII, H-alpha and OIII look really good.

Now, as explained earlier:

Using SHO2, set the formula to SHO2 and click on new formula (this applies that formula) and then recalculate. SHO2 will already reduce the green cast and purple stars:

This immediately looks a lot better 🙂

Now as in my example, I customized the SHO2 formula by mixing a bit more of Ha, SII & OIII to the RGB channels of the composite and by raising the multipliers of both SII and OIII, formula can be seen in this screenshot:

Again looks better ! Green cast is gone and less purple stars, nice blue and red Nebula... and brownish dust. You have very nice data here !

Next step is technically more advanced, but it involves playing with the Luminance of the composite. The H-alpha integration is perfect for this, since that one shows the brown dust surrounding the bright nebula, so I set the L slider of H-alpha to make up 75% of the composite. If you would set it to 100% you might get star border artefacts, so best not to do that and 75% looks really awesome !

In the next post, I will demonstrate futher tweaks with HSL Selective Color 😉

Now to continue, load this result into the HSL Selective Color tool.

First I am going to alter the blue and cyan nebula parts:

I select BLUE and for the data range of the blue pixels the preset of

background + 2*noise - 25% range

looks great to alter the blue nebula, because this is the mask that is shown with show color selection:

I make the nebula more blue (less cyan) by setting the B<-->YE slider to -0,80

I keep this change now by clicking on keep current adjustments. This resets all sliders and manipulations for further tweaks on this result.

Now we go to the red pixels, select RED and try to get a nice mask to influence the brown dust and red nebula parts, background - 25% range is good:

I make them more Red by setting R<-->CY to -0,80 and I injected some yellow to get more colors in there...

Again I keep this by clicking on keep current adjustments.

There is a slight hint of green in some nebula parts which you can see by stretching very weak:

which you can now counter with selecting green and a proper range mask:

And then adding red and blue and desaturating a bit

Again kept it with keep current adjustments... I did some more minor tweaks and then this is great I think:

Final Step as a bonus, I started the Remove Ligth Pollution Tool on this result:

Make sure that you can see all sky background details by over-stretching and over-saturating so we can clearly see what we want to correct 🙂

I save this and then make a final stretch with the preview filter on the right-side:

This is the saved stretched JPG and it's inverse :

Hope this all helps to get a similar result 😉

Hi Michael @msamazing, so to summarize, from SHO1, to SHO custom with Luminance, to HSL Selective Color, to final stretch:

Really nice data to work with 😉 looks great !

Oh, and a tried a star reduced version as well:

@mabula-admin Thank you so much for this.  One issue is that after adjusting the luminance to 75, my image looks a lot different than yours.  Please see the attachment.  It got blown out and is very white.  It seems both of our settings are the same.  What did I do wrong?

Hi @msamazing,

Please check on the right side, you have not yet enable color saturation in the preview filter 😉 Enable saturation with the checkbox and play with the SAT and SAT TH sliders. Then you will see the same as me 😉

Mabula

@mabula-admin That resolved my problem and this was a very helpful tutorial.  Of course I don't understand what everything really does or means at this point. The challenge is how to really learn it when every image is different.  I can't have you doing this every time.  

Any thoughts on how to better learn?

@mabula-admin sorry one more question.  Now that I have the image that I want to keep, do I keep it stretch and save it or?

@msamazing Yes, you stretch it and save it. Note that you can play with the stretch parameters to tweak the result a but further. That is up to your liking. 

@wvreeven done thank you to all of you for your help!!!!! Outstanding Service!

Mabula, that was an *amazing* mini-tutorial! In general I have not gotten good Hubble Palette results. But seeing that tutorial, and practicing on some IC 443 data, it shows me a light out of the wilderness.

Food for thought: APP caters to the beginning imager. Like me 😉 For example, when you talk about shifting Yellow to Blue to get rid of Cyan, looking at the HSL wheel in mind that means adding red to the blue channel. Clearly I have a lot to learn about Color, but I bet I am not the only APP user that does.

Point being with 1.083 stable you would get the user base producing more and better results with more tutorials like that one. 

Fab insight into APP using Hubble pallet & HSL.

I use a OSC camera with a quad band filter for Ha, Oiii and a little Sii

Would the same principles for processing mono Ha, Oiii & Sii as above apply for my OSC and quad band filter?

Thank you 

If I may jump in with what may be a perfectly idiotic question... can the Hubble tool be used on an OSC image?

@safinsd There are no idiotic questions. And, yes it can. Just keep in mind that SII, Ha and OIII images are needed for the Hubble palette. 

@wvreeven Thanks!

Can I just say that Astrobloke has a really good tutorial on using the HSL tool on YouTube?