[Geoff45 (Geoff)]

Really good Slawomir. The Oiii halo has come out very well and the detail in the main nebula is very sharp. I guess 21 hours really pays off.

As a total aside about the colour mapping I have a few suggestions you may want to think about if you want to get pseudo RGB. First think about what would happen with normal RGB. The main lines in general emission nebs are Ha, OIII and Hb. The R filter would record Ha, the green filter would record OIII and the blue filter would record a mixture of OIII and Hb. (OIII sits astride the overlap in the G and B filters, so goes into both channels).
So a reasonable map would be
Ha ->R
OIII -> G
Hb+ OIII-> B.
Now for the sneaky bit. Where does the Hb come from? Hb comes from the same regions as Ha, but at about 25-30% weaker. So if you have an Ha image you also have an Hb image. Just for fun try
Ha -> R
OIII -> G
OIII +20% Ha -> B. Edit should be 80%OIII+20%Ha

Experiment with the ratios in the B channel.
Geoff