Here is an image of NGC6888 - the Crescent nebula which has been processed to remove the stars in order to reveal the nebula structure, which is otherwise largely hidden by stars in the plane of the Milky Way.
The image was taken with a regular One-Shot-Colour (OSC) camera, but fitted with an a dual narrow band filter which only allows light from Hydrogen (Hα at 656.3nm) and doubly ionised Oxygen (OIII at 500.7 & 495.9nm) to pass through. These narrow band filters are useful when taking pictures when the Moon is bright, and with city light pollution.