Propeller Nebula (DWB 111, MRSL 497). This S-like formation is part of the much arge area of emission nebula in constellation Cygnus. There are very little information about the origin and distance of this structure is unknown.br/Technical detail can be found here:
http://www.astroanarchy.blogspot.fi/2014/11/dwb-111-propeller-nebula.html
