How APP calibrate star colors with narrowband data?

Hi @astro_alex,

Thank you for your question and welcome to the APP forum 😉

At the RGB Combination in APP using the RGB Combine tool, no star color calibration is done. There is a separate tool for this in 9) called  Calibrate Star Colors, but this really only works well with broadband data. With narrowband data alone, star color calibration is rather complicated.

The colors in the combination of the RGB composite in your case will depend on the normalization of the data. APP, by default will normalize the narrowband channels, which ensures (in most cases) a very nice starting point for your RGB composite.

Regarding lack of Halos where you would expect one to show up is interesting, maybe you could upload an example of  this?

Thanks,

Mabula

Thanks for your answer, Mabula. 

I assumed there wasn't any star calibration doing the RGB combination process, because there's already a tool for that. I was going to upload an image but can't find how to do it, sorry 

I didn't see the attach files icon, here are two images I processed with APP and PS. Stars were only reduced in size, nothing else.

Hi @astro_alex,

These are great images Alex :-), thank you very much for sharing !

Below and to the left of the textarea where you write your message, is the option to attach images, Attach Files

Kind regards,

Mabula