Eastern Veil Nebula
This is the Eastern Veil Nebula (NGC 6992). This is a portion of a supernova remnant (along with the Western Veil Nebula) located in the constellation Cygnus. This supernova occurred around 9000 years ago and is estimated to be located approximately 2400 lightyears away (although I've seen many estimates at 1500 lightyears distant as well).
I've read that it is suspected that before the supernova, the star expelled a strong stellar wind which blew a large cavity into the surrounding interstellar gas. Later, the shock wave from the supernova expands and hits this previously expelled gas. This wave interacts with the gas to form the nebula's tendrils or filaments and the energy from the supernova excites this gas and and emits the bright colors. Variations in the temperatures and densities of the chemical elements result in different colors in throughout the gas cloud.
Stack of 90 light frames 60s exposures at iso 1600
Unmodified Canon 5dmkIII
William Optics Zenithstar 81 telescope (with field flattener)
Skywatcher HEQ5Pro mount (no guiding).