I was just playing around with my first three narrow band subs of the night and combined the unregistered Ha, OIII and SII subs into a colour image. Because they are unregistered you can see the red (SII), green (Ha) and blue (OIII) stars in little groups rather than superimposed on top of each other.
The Ha signal is the brightest, followed by OIII and SII which is typical for most objects. That means that the SII data has to be stretched a lot more than OIII which is stretched more than Ha to get an even colour combination. This bloats the red and blue components of the stars more than the green which is shown nicely in the attached crop. Register the images and voila... magenta star halos.
I obviously have some spare time on my hands while ACP does the hard work of driving my scope. Hope this was of interest to someone
Cheers,
Rick.