IC1396 - The Elephants Trunk - In bicolor

[jjosefsen]

Captured in late August / early September.

Should be viewed in full resolution. :)

 

Gear used:

AA Hypercam 1600m on a SW 80 ED Pro with matching .85 reduccer and upgraded SW focuser.

Baader 7nm H-alpha and Baader 8.5nm Oiii filters.

EQ6 Pro with rail upgrade.

ZWO 60mm Guide scope with AA Hypercam 183m V2 camera.

 

Software used:

N.I.N.A. for planning, control and acquisition.

PHD2 Guiding, Sharpcap polar alignment.

Astro Pixel Processor for Calibration and stacking, PixInsight for post processing and Photoshop for watermark.

 

Post processing workflow:

Both master aligned in PI and Cropped for same FOV.

 

Ha-master:

DBE for removal of LP gradients.

Deconvolution with starmarsk

Linear noise reduction using various masks and TGVDenoise + MMT.

 

Oiii-master:

DBE for removal of LP gradients.

Stars removed using Starnet++ and Clonestamp.

Heavy noise reduction with MMT

Blur with convolution

 

Combination and non-linear:

LinearFit Oiii master to Ha-master

Linear combination of masters using SHO-AIP script to create RGB-master for tonemapping.

Created "super lum" with 80/20 split of Ha and Oiii masters.

Combination of curves and Histogram transformation for stretching both masters.

Many uses of curves to get colors i like, saturation, etc on RGB-master.

SCNR to remove excess green in RGB-master.

LHE and Curves on super lum for better contrast.

Extract luminance from RGB-master and LinearFit to super lum.

Combine RGB-master with super lum using LRGB combination for a LRGB-master.

A round of curves for better contrast and colors on final LRGB-master.

Final round of noise reduction on LRGB-master using TGVDenoise.

 

Save as JPG and create watermark in Photoshop.

 

Edited October 6, 2019 by jjosefsen

[upahill]

Fantastic shot, and thanks for sharing your process

[kirkster501]

Great work!  How did you create the superlum?  I have not heard of that before.

Say hi to Denmark for me.  My brother is married to a Dane and lives in Roskilde - beautiful place.   Drove there many times.

[tooth_dr]

A beauty Johannes, thanks for sharing 👍🏼

[jjosefsen]

23 hours ago, kirkster501 said:

Great work!  How did you create the superlum?  I have not heard of that before.

Say hi to Denmark for me.  My brother is married to a Dane and lives in Roskilde - beautiful place.   Drove there many times.

Denmark says hi back!

I just reinstalled PI so I need to add some scripts back, but I will give some info on a few ways to blend that luminance later.

[jjosefsen]

On 05/10/2019 at 17:51, kirkster501 said:

Great work!  How did you create the superlum?  I have not heard of that before.

Say hi to Denmark for me.  My brother is married to a Dane and lives in Roskilde - beautiful place.   Drove there many times.

So I have two ways that I blend channels to create these synthetic luminances or super luminances for a lack of a better word.

The target is to create a luminance layer that has the strong SNR of (usually) the Ha master, but won't give you colored rings around stars because the luminance stars are much larger then the Ha stars.

I still feel like it help control star sizes, but it can take some fiddling to get right.

In this HOO image, it also helped bring out the stronger Oiii parts of the nebula as the luminance got a contribution from the Oiii master.

 

1. Using the SHO-AIP script

Really easy to try and blend varying degrees of luminance together, I feel like Screen is  the best method.

 

2. Using PixelMath

The above was from an image of the HaRGB image of the Hearth Nebula, where I didn't shoot any luminance, but i created a Synthetic Luminance by stackign all R,G,B frames into a Luminance master.

I then used the above to enhance blend as much of the Ha into the luminance as I could get away with, as it had much better SNR than the luminance created from the RGB.

The same process could be used in SHO or HOO processing.

You basically just tweak the L_bandwith and Ha_bandwith settings - I believe i ended up using a much small L_bandwith number..

The "super lum" image can look a little strange, but thats ok, it gets blended into the original lum with the below script.

(I can't remembe where I found these formula, but somewhere online.. :))

 

(The SHO-AIP script also uses PixelMath underneath the hood, but I don't know the formula.)

 

Hope this makes sense.. If not I can try and find the original articles online, im sure they will explain much better.

Edited October 7, 2019 by jjosefsen

[Per_jensen]

This is just superb Johannes! I really love the bi color, you see so much hubble pallete these days!  

 

[jjosefsen]

1 hour ago, Per_jensen said:

This is just superb Johannes! I really love the bi color, you see so much hubble pallete these days!  

 

Thanks Per!

I don't have an SII filter so it had to be bicolor.

[kirkster501]

Thanks for the detailed description Johannes, I get it now about the superlum  

Can you explain this line? "Linear combination of masters using SHO-AIP script to create RGB-master for tone mapping."   So you created the "RGB" by HOO combination with that script?

[carastro]

Very nice image.

Carole 

[jjosefsen]

1 hour ago, kirkster501 said:

Thanks for the detailed description Johannes, I get it now about the superlum  

Can you explain this line? "Linear combination of masters using SHO-AIP script to create RGB-master for tone mapping."   So you created the "RGB" by HOO combination with that script?

Yes exactly.

It's just a convenient way to mix different amounts of a given image into the R, G, B channels using a GUI with sliders as opposed to a pixel math formula.

The script can also do some noise reduction and saturation boost.

I had around 8-10 different "blends" i played around with until I had the desired colors, and then tweaked it with curves.

[kirkster501]

20 hours ago, jjosefsen said:

Yes exactly.

It's just a convenient way to mix different amounts of a given image into the R, G, B channels using a GUI with sliders as opposed to a pixel math formula.

The script can also do some noise reduction and saturation boost.

I had around 8-10 different "blends" i played around with until I had the desired colors, and then tweaked it with curves.

Cool - thanks man!