I've developed a procedure where Ha emissions in a galaxy are subtly brought out according to the strength of the emission rather than the typical ultra high contrast view.
I think this procedure has potential as I think I will be able to use it to differentiate between OIII and Ha emissions. Further study is required....
I've picked NGC 55 as the target as the Ha detail is not as obvious as in other galaxies.
Details.
LHaRGB image.
L 4 hrs, Ha 3 hrs, RGB 1 hr each.
BRC 250 scope STXL-11002.
Full resolution.
http://members.iinet.net.au/~sjastro/ngc55newc.html
Clear skies
Steven