[raymo]

To add to your wondering, I actually considerably lowered the highlights in
order to quieten down the blown out core of M42 to allow its delicate colour to show through. Some of my Orion images do show a hint of the Loop, but
none show any sign of M78. Low and mid range Canon DSLRS are not among the best for Ha, but high end models do better. I might try some longer subs
and see if I can bring out the Loop, but I already use ISO 1600 and/or 3200
and f/2 or 2.8, so I will have to use substantially longer subs to have any
chance of bringing out the Loop.There was no sign of the Loop at any stage
of stacking/ processing of this image.

You could even include Rigel [just] with a 50mm lens if you put Rigel in one corner and The Rosette in the diagonally opposite corner, and
even include The Witch.
raymo