Oldest Supernova
The oldest recorded supernova is this one, RCW 86, located 8,000 light-years away in the constellation Circinus. It was noted nearly 2,000 years ago (in 185 A.D.) as a “guest star” in Chinese astronomical documents. Light from the supernova was visible for nearly eight months in the sky before it faded, leaving this amazing remnant behind.
Image: X-ray: NASA/CXC/SAO & ESA; Infared: NASA/JPL-Caltech/B. Williams (NCSU)