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Real luminosity and color references?

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#1 vidrazor

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Posted 18 March 2019 - 01:34 PM

Is there such a thing as a true color reference for recreating objects in the sky as you would see them in real life? Being as apparently all astrophotography is artistic license, I was wondering if such images or references exists. Obviously they wouldn't possess the pizazz of heavily processed imagery, but the thought popped into my head as I peruse through various post processing techniques.



#2 calypsob

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Posted 18 March 2019 - 01:50 PM

In astrophotography you can use a G2v star as a white balance reference. You can push a white balance so that it goes cool into the blues or warm into the yellows. If you think of the color temperature that you see in an led light bulb similar to this image https://cdn.shopify....g?v=1542628347 

A G2v star https://en.wikipedia...n-sequence_star is similar to a 5800k light bulb.

 

So if you want to be "sciency" you can use a G2v star as your reference when you white balance, but the artistic factor does reveal itself here.

You can have the white balance of your stars completely independent from your background nebulositiy if you want to, or you can white balance the whole image, or you can do both separately, combine them and then shift the white balance again. There is no right way to do it, but the G2v method does at least provide some degree of reference for the sake of calibration.  

If you go out of your way to G2v calibrate, it may be in your best interest to describe the trouble that you went to in order to reproduce g2v accurate colors.


Edited by calypsob, 18 March 2019 - 01:50 PM.


#3 the Elf

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Posted 19 March 2019 - 11:37 AM

PixInsight offers a photometric color calibration. The stars are identified by plate solving, the true color is looked up in an online data base and the color balance adjusted as good as possible. This is probably the best you can get today.




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