HA and OII Extracti...
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2023-04-17: APP 2.0.0-beta17 has been released !

RAW support for camera color matrix with Bayer Drizzle integration, fixed couple of image viewer issues.


We are very close now to  releasing APP 2.0.0 stable with a complete printable manual...


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HA and OII Extraction

4 Posts
3 Users
White Dwarf
Joined: 1 year ago
Posts: 6
Topic starter  

First off I love the ability to do this extraction. However, it would be nice if that can be selected as a filter, and than it actually uses that information to do the extraction for both of them.  Currently the workflow to do the extraction is a bit cumbersome as you have too do 2 extractions, than you need to combine them.  I would love to see this workflow get some much needed love as it is a fantastic feature.

Joined: 5 years ago
Posts: 2106

@romonaga Thanks for your comments, Robert. Improving the Ha/OIII extraction is on the TODO list. I am not sure if it will be part of APP 2.0.0 and if it isn't then it will be for a release soon after that one.


Red Giant
Joined: 2 years ago
Posts: 49

I have a question regarding that. i usually do the Ha-OIII Color extraction. How is the third (blue) channel composed? I use that so I can do a fake SHO palette.
But as I understand, it’s better to extract them and then do the combination? 
How do I get the third channel?

It is cumbersome to extract Ha and then OIII and then Ha-OIII to get the the blue channel.
I’ve seen videos that extract the mono channel and make that the third channel. Which would be the best route to choose?
The easiest is the way I do it now, Ha-OIII color -> Split channel -> RGB Combine


Joined: 5 years ago
Posts: 2106

@digitaliz-se Both the Ha and OIII channels are mono channels. To create a color image, you can use the HOO formula in the Combine RGB Tool. That means that Ha will be used for the Red and OIII for both the Green and Blue channels. There are ways to create a synthetic third channel and using that for Red, while using Ha for Green and OIII for Blue to create a fake SHO image. APP doesn't have a specific way for doing that but you can search on internet and then apply accordingly.

HTH, Wouter