The Vela supernova remnant is a supernova remnant (SNR)
about 900 light-years away for a supernova that would have become visible
to Earth about 10,000 years ago.
It is one of the nearest known SN remnants and
is very bright in X-rays.
In the sky, it overlaps a more-distant SNR, Puppis A.
I believe the first noting of it was specifically of a nebula that
forms part of it, which is labeled NGC 2736 or the Pencil Nebula.