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Gee you did a lot of things right there if thats your first mono CCD image. Great sharpness, wonderful round and tight stars which is usually 90% of the battle.
HaRGB is a tough combo. Ha + LRGB is much nicer. Some combine Ha and red together, some Ha and luminance together or both. I use Ha as a separate layer with the green and blue deleted leaving only red and another layer set to blue (by deleting red and green channels leaving only blue) at about 10% both in lighten mode. I usually don't use it for luminance at all although sometimes I use a Ha layer set to luminosity mode and experiment to see if it adds or detracts to the image. Perhaps I would selectively layer in small parts of it to add detail but usually not as it would make the image inconsistent across the frame.Usually I find it just throws the colour balance off or washes out the saturation even if it did give a bit more detail. So usually its not worth it although there are no hard and fast rules and every image can be a bit different. Lighten mode is the key to the layers. You retain total control of Ha content in the final image.
My approach over the years was initially to be heavy handed with Ha that ended up with almost totally red dominated colours. Then I became a bit more subtle. My personal take is to knock Ha back a bit as it is so dominant. John's Ha only images makes a lot of sense as Ha can give great detail but often skews colour images and loses a lot of that detail.
The dreaded salmon colours come from combining Ha into too much luminance. That is the downside of Ha+luminance if not done really well and probably a lot of trial and error for the ideal combo of Ha as red and Ha+luminance for luminosity with little control if you get it wrong. Hence the lighten mode is far better although I should try the other approach a bit more as plenty have demonstrated on this site that it can give good results done well. I think its just a lot harder.
Ha exposures are best done longer than LRGB to make up for the weaker signal that has to overcome the CCD noise. 20 minutes if your tracking is up to it (it seems like it is) would result in lower noise images. John Gleason here is the acknowledged expert on Ha and I notice he uses 40 minute subs (great if your weather is stable).
Greg.
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