This is an image of the Horsehead and Flame with HA assigned to the red channel and NII to the green.
Full res image 8MB
http://d1355990.i49.quadrahosting.co...HH_HA_NII_.jpg
This is a mono made combining both HA and NII data. 5MB
http://d1355990.i49.quadrahosting.co...2_11/12frm.jpg
It is effectively what you would get with a 5nm or wider HA filter.
As you can see for yourself for this area at least there is not much difference between HA and NII.
The NII data does show more detail.
Bert
Exposures: 6x16 minutes for both HA and NII.
Astrograph is an Officina Stellare RH200 which has a focal length of 600mm and is F3, yes F3! Clear aperture is 200mm.
FLI Atlas Focuser.
FLI ten position filter wheel CFW-3-10 with 50mm square filters.
Astrodon E series LRGB and HA, NII, SII and OIII 3nm NB filters. Also a continuum filter 5nm.
Camera is a FLI PL16803 which has a sensor size 36.8 X 36.8 mm.
The FoV of this system is 3.5 X 3.5 degrees.
Mount is a Software Bisque PMX.