CTB 1 (Abell 85) is a faint, filamentary supernova remnant in the constellation of Cassiopeia. Van den Bergh identified this object as a SNR in 1972 based upon its circular shape. The supernova that created CTB 1 exploded some 8,000 - 10,000 years ago. The distance is estimated to be 10,000 light-years, and the span - about 100 light years. There is an unusual breakout structure referred to as a "shell rupture" toward the northeast, which also can be seen on X-Ray images. The image was composed in this way (CTB at the top of the image) in order this breakout structure to be fully covered. Not far from CTB 1 (but physically not related), is the last object of the van der Berg Catalogue - VdB 159 (see mouseover). It is a small reflection nebula, illuminated by the 7.9 mag. star HD 225180. The blue color of the star (spectral class B9IV) gives the same tinge to the nebula.