IC4592 The Blue Horsehead is faint, very faint at 800mm F/L.
Even with 8 inches of astrograph!
Played with this image for a while to bring out the faint extended nebula.
I've also supplied a wide field to show IC 4592 in context and a single sub to show how faint it is.
8” F/4 astrograph , baader type 3 coma corrector,. HEQ Pro 5 mount, orion mini guider.
Camera.
Unmodded Cannon 1100D plus cooler box. 48 subs x 2 minutes at ISO 6400. Stacked in Deep Sky Stacker .Processed in Photoshop Cs2..