Just beautiful Jorge, with all those different exposures you've captured a whole lot of detail, it's not often that you see the trapezium in the centre. Great detail overall!
And now, a mosaic of two photos: M42 and Running Man
M42 - GSO 305mm - Canon Rebel XT - 11 x 120 s iso 800; 4 x 60 s iso 400; 4 x 30 s iso 400 - Vixen 70mm DSI Meade
Running Man - GSO 305mm - Canon Rebel XT - 12 x 120 s iso 800 - Vixen 70mm DSI Meade
Excellent handling of the bright area there Jorge, the handling of this area is rarely done well, with the blending almost always looking obvious but you have done a seamless job here
You've really done our favourite nebula justice here with blending in the shorter exposure trapezium!
I do feel though that your data perhaps has a little bit more detail to give than you are showing us here by more carefully managing your dynamic range (example attached).
Thanks, all you by comments. Really the process was well done. But, undoubtly I must learn much more. The example of Ivo showed it. Special thanks to you, Ivo. I will try a repro.
Attempt of repro, with a method different from processing. It emphasized more the blue color, and unhappily a bit more of noise. Though the image appear to be more sharp, I think that I prefer the most reddish version.