Here is IC 4628 and surrounds in HA and O3 combined to give a 'colour' image. The Dark Tower is near top left of center.
Large Image 8MB Fov 6.4 X 4.4 degrees.
http://d1355990.i49.quadrahosting.co.../ic4628_NB.jpg
Taken with the 300mm lens. Astronomik 13 nm HA and O3 filters.
20x (120s & 240s) at 1600 ISO. Fridge at -7C. Dithered and HDR.
Bert