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Question about Calibrate Star Color  

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(@jratino)
Molecular Cloud Customer
Joined: 1 year ago
Posts: 4
October 12, 2021 00:20  

Is it normal for the color of the nebulosity to change after performing Calibrate Star Color?  The attached screen grabs of the Lobster Nebula and surrounding objects changed from red (image on the top) to the image on the bottom.

I believe this the first time this has occurred.

Thanks

Jeff

Lobster Claw   no csc
Lobster Claw   csc
This topic was modified 2 months ago by Jeff Ratino

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(@jratino)
Molecular Cloud Customer
Joined: 1 year ago
Posts: 4
October 12, 2021 00:24  

Here are two more images.  Again the top, red image is before calibration.

Lobster Claw session 1 session 2 lpc cbg no csc
Lobster Claw session 1 session 2 lpc cbg St

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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 3961
October 12, 2021 09:01  

It is yes, the tool calibrates the color of the entire image, based on the stars. However, this won't work well with narrowband data as the tool needs broad spectrum data.


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(@jratino)
Molecular Cloud Customer
Joined: 1 year ago
Posts: 4
October 12, 2021 18:58  

@vincent-mod OK Thanks. This was shot with an Optolong L-enhance Filter, Ha mod Nikon D5300 and WO Z61.  Interesting that this is the first time I have noticed this.  I'll have to go back and check my last few images to see if there was a big difference.  And I just didn't catch it. 


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(@jratino)
Molecular Cloud Customer
Joined: 1 year ago
Posts: 4
October 13, 2021 03:29  

@vincent-mod In your opinion then I should not use this tool when I use this filter, correct? 

I did look back at a couple of my other shots and sure enough, the nebula did change.  I don't know how I didn't notice it before.


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 3961
October 13, 2021 09:27  

You shouldn't indeed, the tool can't use narrowband data to properly calculate the correct colors. So in case of data like that, it becomes more of artistic processing. 🙂 Of course you can always look up the colors that belong to a certain wavelength (for Ha for instance) and try to represent that.


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