M78 is my Point of Obsession (but thanks to wonderful QLD weather, still haven't had a crack in ages).
Agree with Paul. I think my M78 with the FL102S was up to around 10 hours and noisy as snot, but the detail was coming out.
What is surprising in your image is the lack of H-a emmission - there is an abundance of H-a around M78, that even my Fl102S and the ancient ST-8Xe STARTED to reveal (and was more aparent in my FSQ-85 images with the FLI). have alook at marco's image to see the amount of H-a around. Perhaps the cooled DSLR isn't picking it up so much?
Anyway, BEAUTIFUL image - in fact, I think better than at least 95% I have seen out there, even some taken with large instruments and high end CCD's.
Keep at it. VERY envious you can image my jewel