Video: M42 H-alpha High Dynamic Range composite processing

[admin]

Hi all,

A new tutorial video has been released!

In this video we process a magnificent multi-exposure length Hydrogen-alpha data set that was so graciously donated to the public domain by Josh Lake of the Olmsetd Observatory at Pomfret School.

We process two exposure lengths independently, and combine them into a high dynamic range image. After combining, we modify the presentation of the image to match the data provider's personal taste by scaling down the image and performing some delicate sharpening.

The final result can be found here.
This video uses data from Josh Lake that can be downloaded here.

[trobbet]

Hello,

I have been trying to use this High Dynamic Range method, but I can't figure out how to get my long exposure stack to synch with the short exposure one. I can, with some difficulty, get them to be the same size after cropping, but although the short exposures were done with same equipment following the longs on the same night, stars aren't lining up in the Layer module. I'm hoping there is more automatic way to get both the longs and shorts to line up.

Not only do I have that problem, I'm finding getting the general shade of both stacks seems very difficult, and important to make the layers module work satisfactorily. I'm not using the color module before the Layer module, but I wondering if the method in the tutorial works as easily for a color image.

Any enlightenment will be appreciated...

CS, Tom

[admin]

Hi Tom,

Aligning your data sets is something that fits more in the realm of pre-processing. If you're using DSS you can use one stack as a reference frame to align the others against (without using the stack in the stacking result).

Could you tell us your processing flow? You should be able to arrive at the same coloring even when processing different data sets. What version of StarTools are you running?

[trobbet]

Thanks Ivo!

I'm using .279.

I use Nebulosity, and I think there may be a way to align my two sets there. I will try in the next couple of Days. If I were to find a way to crop the files together in Nebulosity, in order to synch them and make them the same size, would that make my files "non linear", and mess up their use in StarTools?

As far as processing flow, I was attempting to emulate the processing taught in the tutorial. I could include a copy of my log, if that's what you would like.

Cheers, Tom

[admin]

If I were to find a way to crop the files together in Nebulosity, in order to synch them and make them the same size, would that make my files "non linear", and mess up their use in StarTools?

It shouldn't - making data non-linear pertains to the way brightness livels pixels are non-lineary tranformed so that we can see them (for example by using a gamma correction curve or digital development, etc.). Cropping is totally fine!

As far as processing flow, I was attempting to emulate the processing taught in the tutorial. I could include a copy of my log, if that's what you would like.

That'd be very helpful to find out why colour is different between the two stacks. Thanks!

[trobbet]

OK, Here's my latest attempt. My plan was to combine the 2 processed stacks, and the use the color module with the resulting image, but besides being out of synch my resulting short image is darker than my resulting Long, and they look funny cobined, at least at this point.

StarTools 1.3.5.279
Sun Apr 13 16:32:48 2014
-----------------------------------------------------------
File loaded [/Users/trobbe/Documents/NEB J 1 Folder M 42 long 170/M 42 Long 35X170.fit].
---
--- Bin
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [69.26 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [5.0 pixels]
--- Crop
Parameter [X1] set to [109 pixels]
Parameter [Y1] set to [65 pixels]
Parameter [X2] set to [2579 pixels (-41)]
Parameter [Y2] set to [1735 pixels (-70)]
--- Wipe
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [UNKNOWN] set to [No]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [1 pixels]
Parameter [Drop Off Point] set to [100 %]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [75 %]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [90.29 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [Off]
--- HDR
Parameter [Small Detail Precision] set to [Max]
Parameter [Channels] set to [Brightness Only]
Parameter [Algorithm] set to [Equalize]
Parameter [Dark/Bright Response] set to [1.00]
Parameter [Detail Size Range] set to [21 pixels]
Parameter [Noise Suppression] set to [Off]
--- Wavelet Sharpen
Parameter [Intelligent Enhance] set to [Yes]
Parameter [Scale 1] set to [100 %]
Parameter [Scale 2] set to [100 %]
Parameter [Scale 3] set to [100 %]
Parameter [Scale 4] set to [100 %]
Parameter [Scale 5] set to [100 %]
Parameter [Mask Fuzz] set to [6.0 pixels]
Parameter [Amount] set to [206 %]
Parameter [Small Detail Bias] set to [75 %]
Undo.
--- Wavelet Sharpen
Parameter [Intelligent Enhance] set to [Yes]
Parameter [Scale 1] set to [100 %]
Parameter [Scale 2] set to [100 %]
Parameter [Scale 3] set to [100 %]
Parameter [Scale 4] set to [100 %]
Parameter [Scale 5] set to [100 %]
Parameter [Mask Fuzz] set to [6.0 pixels]
Parameter [Amount] set to [205 %]
Parameter [Small Detail Bias] set to [75 %]
--- Deconvolution
Parameter [Image Type] set to [Deep Space]
Parameter [Mask Behavior] set to [De-ring Mask Gaps, Hide Result]
Parameter [Radius] set to [2.6 pixels]
Parameter [Iterations] set to [6]
Parameter [Regularization] set to [1.00 (optimal noise and detail)]
Parameter [Mask Fuzz] set to [8.0 pixels]
--- Wavelet De-Noise
Parameter [Scale 1] set to [90 %]
Parameter [Scale 2] set to [90 %]
Parameter [Scale 3] set to [90 %]
Parameter [Scale 4] set to [90 %]
Parameter [Scale 5] set to [0 %]
Parameter [Mask Fuzz] set to [1.0 pixels]
Parameter [Scale Correlation] set to [3]
Parameter [Color Detail Loss] set to [14 %]
Parameter [Brightness Detail Loss] set to [14 %]
Parameter [Redistribution Kernel] set to [4.5 pixels]
Parameter [Read Noise Compensation] set to [Off]
Parameter [Smoothness] set to [75 %]
File saved [/Users/trobbe/Documents/M 42 Long no color 2470X1670.tiff].
File loaded [/Users/trobbe/Documents/m 42 short no color.tiff].
---
File loaded [/Users/trobbe/Documents/NEB J 1 Folder m 42 short/m42 short 27X 4 .fit].
---
--- Bin
Parameter [Scale] set to [(scale/noise reduction 50.00%)/(400.00%)/(+2.00 bits)]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [83.82 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [7.6 pixels]
--- Crop
Parameter [X1] set to [121 pixels]
Parameter [Y1] set to [69 pixels]
Parameter [X2] set to [2470 pixels (-132)]
Parameter [Y2] set to [1670 pixels (-69)]
Undo.
--- Crop
Parameter [X1] set to [100 pixels]
Parameter [Y1] set to [57 pixels]
Parameter [X2] set to [2570 pixels (-32)]
Parameter [Y2] set to [1725 pixels (-14)]
--- Wipe
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [UNKNOWN] set to [No]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [1 pixels]
Parameter [Drop Off Point] set to [100 %]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [75 %]
--- Develop
Parameter [White Calibration] set to [Use Stars]
Parameter [Gamma] set to [1.00]
Parameter [Skyglow] set to [0 %]
Parameter [Digital Development] set to [90.61 %]
Parameter [Blue Luminance Contrib.] set to [100 %]
Parameter [Green Luminance Contrib.] set to [100 %]
Parameter [Red Luminance Contrib.] set to [100 %]
Parameter [Dark Anomaly Headroom] set to [5 %]
Parameter [Dark Anomaly Filter] set to [Off]
--- HDR
Parameter [Small Detail Precision] set to [Max]
Parameter [Channels] set to [Brightness Only]
Parameter [Algorithm] set to [Equalize]
Parameter [Dark/Bright Response] set to [1.00]
Parameter [Detail Size Range] set to [21 pixels]
Parameter [Noise Suppression] set to [Off]
--- Wavelet Sharpen
Parameter [Intelligent Enhance] set to [Yes]
Parameter [Scale 1] set to [100 %]
Parameter [Scale 2] set to [100 %]
Parameter [Scale 3] set to [100 %]
Parameter [Scale 4] set to [100 %]
Parameter [Scale 5] set to [100 %]
Parameter [Mask Fuzz] set to [7.2 pixels]
Parameter [Amount] set to [200 %]
Parameter [Small Detail Bias] set to [75 %]
--- Deconvolution
Parameter [Image Type] set to [Deep Space]
Parameter [Mask Behavior] set to [De-ring Mask Gaps, Hide Result]
Parameter [Radius] set to [2.0 pixels]
Parameter [Iterations] set to [6]
Parameter [Regularization] set to [1.00 (optimal noise and detail)]
Parameter [Mask Fuzz] set to [8.0 pixels]
--- HDR
Parameter [Small Detail Precision] set to [Max]
Parameter [Channels] set to [Brightness Only]
Parameter [Algorithm] set to [Reveal DSO Core]
Parameter [Dark/Bright Response] set to [Full]
Parameter [Detail Size Range] set to [64 pixels]
Parameter [Noise Suppression] set to [Off]
--- Wavelet De-Noise
Parameter [Scale 1] set to [90 %]
Parameter [Scale 2] set to [90 %]
Parameter [Scale 3] set to [90 %]
Parameter [Scale 4] set to [90 %]
Parameter [Scale 5] set to [0 %]
Parameter [Mask Fuzz] set to [1.0 pixels]
Parameter [Scale Correlation] set to [3]
Parameter [Color Detail Loss] set to [18 %]
Parameter [Brightness Detail Loss] set to [17 %]
Parameter [Redistribution Kernel] set to [4.5 pixels]
Parameter [Read Noise Compensation] set to [Off]
Parameter [Smoothness] set to [75 %]
File saved [/Users/trobbe/Documents/m 42 short no color 2470X1668.tiff].
File loaded [/Users/trobbe/Documents/M 42 Long no color 2470X1670.tiff].
---
--- Crop
Parameter [X1] set to [0 pixels]
Parameter [Y1] set to [0 pixels]
Parameter [X2] set to [2470 pixels (-0)]
Parameter [Y2] set to [1668 pixels (-2)]
File saved [/Users/trobbe/Documents/M 42 Long no color 2470X1668.tiff].
File loaded [/Users/trobbe/Documents/m 42 short no color 2470X1668.tiff].

Thanks again for your very speedy attention, Tom

[trobbet]

Ivo,

After quite some work I was able to get the short and long file to synch. I tried both 1/2 unity and the other suggested filter, and this is where I am:

Can this image be made to work the way i would like?

Cheers, Tom

[admin]

besides being out of synch my resulting short image is darker than my resulting Long,

Hmmm.... Isn't that to be expected? Could you maybe post the two results as a jpeg in this thread?

Scratch that... I just saw your images. The issue is simple; you're not suuplying a FIlter Kernel radius! (play around with that parameter until you get a nice blend)
You should also be able to use Offset X and Offset Y to align the frame better (it doens't do rotation though).

I also notice that you don't use the color module at all - this is definitely recommended!

Let us know how you get on,

[trobbet]

Thank you again Ivo!

I thought it was probably something simple. Somehow I missed the Filter Kernal radius in the tutorial.

And I didn't notice the Offset X and Y controls right there in the Layers window. Very handy! I continue to be impressed with your software the more I learn how to use it!

I purposely held off on using the Color Module, thinking perhaps erroneously, that color was getting in the way of my blending the 2 stacks together. This was before I understood to use the Filter Kernal radius. I thought maybe it best to run the Layers module before the color and it may help the 2 stacks merge more aesthetically. So, I have gone ahead for now, and tried that. Do you think it better to add color individually on each stack?

Anyhow, for now I'm still working on getting satisfactory coloring and fine tuning this image. Once I do I'll post a link to it.

Thanks very much for the help.

CS, Tom

[trobbet]

OK, here's my current product, emulating with some personal interpretation the method used in the above tutorial. I did wait to add color after using Layers to combine the 2 stacks. I would love to hear comments... Also, I may do it all over using the Color module individually for each stack. Any opinions?

PS I can provide the current log if desired.

Thanks for looking.

http://astrob.in/full/90745/0/