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Author Topic: Color Cal all images?  (Read 3408 times)

Offline John Massey

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Color Cal all images?
« on: 2015 July 28 12:19:36 »
I'm very new to PI so I have questions(who doesn't?) after combining NB images in SHO is it a good idea to color calibrate the combined image? Thank you in advance for your replies.
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Offline jkmorse

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Re: Color Cal all images?
« Reply #1 on: 2015 July 29 16:05:46 »
I don't think it makes sense to do a color calibration on a narrowband image since that technique is really trying to balance the RGB channels.  There are some great posts on using SHO for narrowband that you should look into, including this one:

http://pixinsight.com/forum/index.php?topic=8706.0

Best,

Jim
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Really, are clear skies, low wind and no moon that much to ask for? 

New Mexico Skies Observatory
Apogee Aspen 16803
Planewave CDK17 - Paramount MEII
Planewave IFR90 - Astrodon LRGB & NB filters
SkyX - MaximDL - ACP

http://www.jimmorse-astronomy.com
http://www.astrobin.com/users/JimMorse

Offline RickS

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Re: Color Cal all images?
« Reply #2 on: 2015 July 29 21:46:00 »
Quote from: John Massey on 2015 July 28 12:19:36
I'm very new to PI so I have questions(who doesn't?) after combining NB images in SHO is it a good idea to color calibrate the combined image? Thank you in advance for your replies.

I think it is worth trying.  If you use CC with the whole image as the white reference (structure detection disabled) then you'll get a reasonable balance between the colours.  If you don't like the result then try something else  ;)

My usual starting point for SHO is to LinearFit the Oiii and Sii to the Ha data and then do a LRGBCombine.

Cheers,
Rick.
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Offline John Massey

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Re: Color Cal all images?
« Reply #3 on: 2015 July 30 05:35:10 »
Thank you gents! Ricks I usually do a Linear Fit before combining LRGB thinking that would actually do the color balance. Thank you for the link JKmorse, many different things to experiment with in PI.
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Offline jkmorse

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Re: Color Cal all images?
« Reply #4 on: 2015 July 30 11:43:20 »
John,

If you are interested, I have a detailed Cribsheet that others have found useful and it includes a detailed workflow as well as details on most of the main tools.  Its too large to post here but if you are interested just drop me a note at jkmorse57@gmail.com and I will be happy to send it along.

Best,

Jim
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Really, are clear skies, low wind and no moon that much to ask for? 

New Mexico Skies Observatory
Apogee Aspen 16803
Planewave CDK17 - Paramount MEII
Planewave IFR90 - Astrodon LRGB & NB filters
SkyX - MaximDL - ACP

http://www.jimmorse-astronomy.com
http://www.astrobin.com/users/JimMorse

Offline RickS

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Re: Color Cal all images?
« Reply #5 on: 2015 July 30 15:50:15 »
Quote from: John Massey on 2015 July 30 05:35:10
Ricks I usually do a Linear Fit before combining LRGB thinking that would actually do the color balance.

John,

I find this a useful starting point but I typically do a lot of additional work on the colour using tools like SCNR and curves (especially in conjunction with ColorMask.)  It's false colour so we can do what we like, right  :D

Maybe some helpful info here too: http://pixinsight.com/forum/index.php?topic=7751.0

Cheers,
Rick.
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Offline John Massey

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Re: Color Cal all images?
« Reply #6 on: 2015 July 30 17:30:55 »
Thanks Rick, I have never liked using Selective colors in PS. I have downloaded and installed the script and will give it go.
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