The distance estimation (~5200 ly) is from Distance of "Three Supernova Remnants from H1 Observations
in a Complex Region: G114.3+0.3, G116.5+1.1 and CTB 1 (G116.9+0.2)" by Uyaniker, et al, July 2003.
CTB1 is also known as Abell 85. Additionally, the brighter part, towards the bottom of the ring in this image,
is LBN 576, from Lynds Bright Nebula list. The name "CTB1" refers to CalTech "B" List, from Table 2 of the
paper "A Survey of Galactic Radiation at 960 Mc/s" by CalTech's R.W. Wilson and J.G. Bolton.
Abell listed the object in his planetary nebula list. Later the object was comfirmed to be a supernova remnant.
The object is very dim. As you can see, it doesn't appear visually in the pure luminance, green, and blue
channels and is barely visible in the red channel. One really needs narrow-band imaging to capture the object's
The composite luminance channel (below) is a combination of the pure luminance, Hα, and Oiii channels. This
provides the luminance support for the two high-quality narrow-band channels.