Just for a little bit of info the reason why you havn't caught the horse head isn't because it isn't "bright" (well it isn't really bright
) but to a DSLR you have a UV IR filter that cuts off the light coming out of Ha regions by a fair way so if you wanted to capture this target irrispective of dark skies or light polluted skies you will need to remove the filter or move to a Astro CCD that is sensitive to this light band.
This is a photo of the HH taken from the middle of South perth (you cannot see the LMC/SMC even if you try) with a Canon 350D with a filter modification on a skywatcher 8" Dobsonian. Just so you know it is possible!
http://s700.photobucket.com/albums/w...lames_web4.jpg