How to Create Synthetic Green Channel??

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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whixson
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Joined: Wed Apr 03, 2013 4:51 pm

How to Create Synthetic Green Channel??

Post by whixson »

Hi! I've taken some narrow band bi-color images of the Veil in Red (H-A) and Blue (O-III). I'd like to blend the R and B to create a synthetic Green and paste it into the G channel of the LRGB module.

Also does it make sense to create a synthetic L channel with the data I have?
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admin
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Re: How to Create Synthetic Green Channel??

Post by admin »

Hi,

The LRGB module by default will already create a synthetic green channel for you if you load the red and blue channels with data (you can switch off this behavior as well).
If you require anything else but a 50/50 blend for the green channel, then you can create your own blend using the Layer module by loading the two frames (as grayscale) in the fore/background, set the blend amount you require and save the result. You can then import that result as your green channel in the LRGB module.

It may be useful to create a synthetic L channel if your Ha/OIII stacks are of different total exposure lengths, else your L will be a 50/50 mix of signal from Ha and OIII.

Does that help?
Ivo Jager
StarTools creator and astronomy enthusiast
whixson
Posts: 51
Joined: Wed Apr 03, 2013 4:51 pm

Re: How to Create Synthetic Green Channel??

Post by whixson »

That's great Ivo. Works like a charm, although I did have more O-III data than H-a. 190 minutes vs 160 minutes respectively. And the H-a data is noisier and not as clear and that shows in my image when I processed it. What isn't clear is if I layer them and weight them, which way? Seems like you might want to weigh the H-a heavier to better balance it? Or do you weigh the O-III heavier, specifically 190/350?

Thanks again,

Wayne
whixson
Posts: 51
Joined: Wed Apr 03, 2013 4:51 pm

Re: How to Create Synthetic Green Channel??

Post by whixson »

Here's a link to the image. Primary processing in ST with color tuning in Lightroom

http://spaceweathergallery.com/indiv_up ... qm3k68ceg3
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