This is a center crop of Sh2-308, AKA The Dolphin Head Nebula in the constellation "Canis Major".
This was imaged through Baader 7.5nm HAlpha & OIII narrowband filters using my full spectrum modded and cooled Canon 40D DSLR and the Bosma 80mm refractor at 500mm focal length. This photo consists of 46x1200s of HII, 35x1200s and 2x600s of OIII and 36x60s, 32x150s and 21x210s of RGB subs @ ISO1600 for a total exposure time of 30.5 hours.
This object is very weak in HAlpha signal but very strong in OIII. The benefit of a color camera is that I captured two spectra lines in one exposure, I had OIII signal in the green channel while simultaneously captured HBeta in the blue channel in the stack. I assembled this image as HAlpha as Red, OIII as green and HBeta as blue.
The weak HAlpha signal outlined some parts of the bubble (the front of the dolphins head) so even if the HAlpha was weak, it was not a waste of time as it added detail to the image.