I am very new at all this, and am on a steep learning curve, so apologies if this is a dumb question.... I recently shot a subject with LRGB, Ha, Oiii and Sii filters. Is there any point in using all of these (the subject was a spiral galaxy, not a nebula) in APP, or should I just use the LRGB for it?
Like we mention more often, there are no dumb questions. 🙂 Maybe you learned that in school, we really don't care and are happy to answer any question you may have.
For galaxies it won't make a lot of difference indeed. Maybe if you can see some Ha regions in the galaxy, like in M31, it does help to add some Ha signal to the mix. I would advice to just try it basically, you can save the split frames (into R, G and B) and then combine them in the CombineRGB tool with 50% R and 50% Ha for instance. If that really doesn't add anything or even reduces the result, just go with the RGB.