Rosette, NGC2244 with NB filters 11h20 exposure (by Trois_Merlettes)
This is a false colour long exposure of the nebula NGC2244. The square blue region from OIII light reveals well the hotter region. Hydrogen is everywhere (green) and there are a few patches of sulphur (red but becoming yellow when combined with the dominant green from hydrogen).
31 subs of 10’ in Ha set to green.
18 subs of 10’ in SII set to red.
19 subs of 10’ in OIII set to blue.
Total 11h20’ ; 127 mm refractor at F5.6; STL 11km.