HFG1 and Abell6, two very faint and unique nebulas in the constellation Cassiopea.
The shape of HFG1 is formed by a system of binary stars orbiting each other and moving very fast through the Milky Way. The power of the system creates a shockwave as it is moves through the interstellar medium, clearly visible by the blue circle around the core of the nebula.
The image is combined in HOO narrowband palette, for a total 6h35m Oiii and 10h Ha. Ha emission is extremely faint and requires many hours of integration to even grab a small portion of it.
High resolution image here