IC 2177, the Seagull nebula in Narrowband adjusted HST palette. This shows only the "head" of the seagull (and is pretty much upside down).
Taken over three nights in January 2014, Hydrogen Alpha 5 and a quarter hours, Sulphur II 3 hours and Oxygen III 2 hours.
This object is rich in hydrogen, but there is significant amounts of sulphur as well, there isn't much oxygen, I had trouble teasing the OIII data to get a useable amount of blue into the picture.
The relative amount of H:S has been tweaked a bit to give a pleasing result, or the image would be dominated by the Ha data and be bright green.
Larger version available
here
Cheers
Stuart