SNR Candidate G70.5+1.9 in Cygnus
G70.5+1.9 is a candidate supernova remnant discovered in 2009. It measures approximately 5x3 arcminutes and its beautiful structure consists of a series of interlocking elongated and curved filaments with its southern rim being the brightest part. OIII in particular reveals an impressive tail structure with a length of 8 arcminutes that extends to the left. The publication about the discovery can be found here.
Further to the south is the Sh2-100 emission nebula complex (left) and Sh2-99 (right).
The image is a combination of long exposed narrowband data (Ha, OIII) with RGB data. North is up in this image.
[description from Sakib Rasool]