3C 58 (SN 1181) in Cassiopeia
3C 58 is a small obscure supernova whose optical component was discovered in 1977 by Sidney van den Bergh on long exposed plates from the 5m reflector at Mt. Palomar. It is the remnant of SN 1181 making it younger than the Crab Nebula but older than Cassiopeia A. The size is about 6x10 arcminutes and required long Ha and OIII exposures.
The small planetary nebula to the right of the image is G130.4+03.1 (PN K 3–92) discovered by Kohoutek 1972. North is up in this image.
The original paper about the discovery of the optical component of 3C 58 can be found here.
[description from Sakib Rasool]