Author Topic: M31 with CLS filter  (Read 5030 times)

Offline Alfredo Beltran

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M31 with CLS filter
« on: 2013 November 07 19:11:07 »
Hi

I've been having some trouble getting the right color balance for this image of M31. It was taken with a C9.25 Edge Hyperstar, an unmodified Canon T1i DSLR and an astronomik CLS filter. Exposure time is 5hr 36 min.

I don't know if that is because of the blue cast given by the filter as a consecuence that it blocks the yellows and oranges, or a problem in the postprocessing, or both.

Here is the link to the unprocessed stacked FIT: https://www.dropbox.com/s/64uf9fl7cg6pidv/M31%20V0A.fit

Your help will be much appreciated.

Best regards,

Alfredo
iOptron CEM60
Celestron 925 EdgeHD Hyperstar
MicroTouch Focuser
ZWO ASI071 MC Pro
Bogota, Colombia
http://www.flickr.com/photos/alfredo_beltran/

Offline Zocky

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Re: M31 with CLS filter
« Reply #1 on: 2013 November 08 13:35:30 »
Hi Alfredo,
Here is my work flow, I hope it will be helpful.

First I`ve cropped the image using DynamicCrop
 
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #2 on: 2013 November 08 13:35:52 »
After cropping Background Neutralization was applied.
   
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #3 on: 2013 November 08 13:36:16 »
Next I`ve used DynamicBackgroundExtraction.
You have to manually apply few extra samples to enhance extraction.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #4 on: 2013 November 08 13:36:37 »
After DBE, an SCNR was applied to reduce green glow.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #5 on: 2013 November 08 13:36:55 »
Now it`s time for HistogramTransformation.
I`ve applied STF to Histogram.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #6 on: 2013 November 08 13:37:13 »
To darken image a bit, CurvesTransformation was applied.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #7 on: 2013 November 08 13:37:31 »
From image I`ve extracted L component to create a mask. Use CurvesTransformation to darken the mask, and then apply the mask to the image.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #8 on: 2013 November 08 13:37:48 »
With created mask it`s time to give a saturation bust to the image.
Apply CurvesTransformation a couple times, until you happy with the result.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #9 on: 2013 November 08 13:38:04 »
Next on the list is LocalHistoramEqualization.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #10 on: 2013 November 08 13:38:20 »
DarkStructureEnhance
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #11 on: 2013 November 08 13:38:35 »
And finally, again some CurvesTransformation, to balance the background.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Zocky

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Re: M31 with CLS filter
« Reply #12 on: 2013 November 08 13:38:55 »
And here is the final image.

Best regards
Zoran
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/

Offline Alfredo Beltran

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Re: M31 with CLS filter
« Reply #13 on: 2013 November 08 13:52:34 »
Well Zoran, a very good result in a few simple and powerful steps. I will try to re process again the image.

One question: why didn't you use Color Calibration? To me, I think it is always necessary as the Background Neutralization. Am I wrong?

Best regards

Alfredo
iOptron CEM60
Celestron 925 EdgeHD Hyperstar
MicroTouch Focuser
ZWO ASI071 MC Pro
Bogota, Colombia
http://www.flickr.com/photos/alfredo_beltran/

Offline Zocky

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Re: M31 with CLS filter
« Reply #14 on: 2013 November 08 13:57:10 »
One question: why didn't you use Color Calibration?
I use ColorCalibration if necesary after DBE, because DBE can correct color very well, and I think it did a good job here.
Skywatcher ED 80/600 with FF/FR x0.85; HEQ5-pro mount
SBIG ST-8300M, FW5 with Baader LRGB Ha7nm filters
https://www.flickr.com/photos/zoran-novak/