Adding Ha to existing image

This is the first time I am combining multiple images taken with separate filters. I have read the RGB composition tutorial and tried to add Ha by combining L, R, G, B and Ha.
As soon as I add Ha the image turns a deep red eventhough I have selected the specific Nm for Ha. I have read that the Ha should be lightened which I havent done (unless Siril takes care of that) so I am assuming thats what is causing the overall red. I am assuming that I am doing something wrong hence need help.
I am practicing with data provided here. IKO - M81 & M82 LRGB+Ha Data Release - August 2021 - IKI Observatory - Stargazers Lounge
Any help appreciated.

Hi, adding a red layer to an already red-green-blue image will give you twice the red so overall the image will be red. What’s explained in the tutorial is that the amount each red image will contribute to the final should be lowered, in general by assigning a half-bright red to both the red and the H-alpha image.

Note that all images used in the colour composition tool should have had their histogram stretched before use.

1 Like

Should have read the tutorial more clearly :slight_smile:

Having said that is there a way to add a Ha image to an existing RGB one, other than to split it into components and then reintegrate into a ha-rgb image?

So far one need to split the rgb.

1 Like