Green cast on final...
 
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Green cast on final integration with duoband subs  

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(@7imlooigmail-com)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 6
January 19, 2021 14:56  

Hi, apologies if this has been answered in another forum but I cannot find the answer. I am new to OSC processing in APP. I keep getting a significant green cast across the whole frame in the final integration regardless of what setting I choose in step 0, I have checked and unchecked force cfa devayer, tried both AAD and Ha-Oiii-color algorithms and they show no diff with strong green cast. I can however use the Ha extract and the Oiii extract algorithms successfully and later combine them into HOO bicolor but I can’t  understand why I am getting that strong  green cast. See attached photos. I have also included the Ha and Oiii separate integrations which seems fine in mono. 

F4222CCF 3819 4B5B 98F9 F2283CE5B594
EC4C390D 510B 429A B84E A77643F7A6E4
D66C49FF 3A16 48F5 AD42 4D6069210A93

 

This topic was modified 1 month ago by Tim Looi

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(@wvreeven)
Galaxy Admin
Joined: 2 years ago
Posts: 586
January 19, 2021 15:06  

@7imlooigmail-com Hi Tim, do you also get the green cast when you enable Neutralize-BG in the upper right? What camera are you using? And what software to shoot the images? What calibration files?


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(@7imlooigmail-com)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 6
January 19, 2021 15:54  

@wvreeven I haven’t tried to check the neutralize-BG in the normalization step 5 yet, will try that, am using darks, flats and dark flats cal subs. Using asi183MC pro and acquisition in asiairpro. In asiairpro the subs were not showing green cast in RGB tho see photo attached

A058F167 9259 4874 B55A 0883F340EDE3

 


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(@wvreeven)
Galaxy Admin
Joined: 2 years ago
Posts: 586
January 19, 2021 16:00  

@7imlooigmail-com I didn't mean Neutralize BG in tab 5 but the checkbox once the integration is done. See the checkbox that the red arrow is pointing to in this screenshot:

Screenshot 2021 01 19 at 15.58.41

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(@7imlooigmail-com)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 6
January 19, 2021 22:31  

@wvreeven ah that fixed it, thank you. Is this something we need to do all the time with duo-narrowband filters? Just trying to understand where the green is coming from, cheers


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(@wvreeven)
Galaxy Admin
Joined: 2 years ago
Posts: 586
January 19, 2021 22:36  

@7imlooigmail-com To be honest, I am not quite sure myself. OSC have twice the amount of green pixels than red or blue and that certainly accounts for part of it. But the OIII signal is much fainter than Ha so I'd expect a more or less neutral background to begin with. But I see it in my pics as well so perhaps there is a lot more green noise than red or blue which causes this effect. In any case, I'm glad that neutralizing the background like that worked.


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