The first entry in Messier's list of deep sky object is the Crab Nebula, the glowing remains of a star that was seen exploding as a supernova in 1054 by the Chinese. It consists of scattered stellar remnants plus a pulsar-wind nebula driven by the neutron star produced in the supernova. It is about 6,500 light-years away in the constellation Taurus and is also cataloged as NGC 1952. The hydrogen-alpha frame is shown below.

Compare the Crab to other supernova remnants, the Jellyfish and the Veil Nebulae.

On May 19, 2023 a new supernova was observed in galaxy M101.

120 minutes L and 112 minutes RGB on 2012-02-20 plus 8 hours H-a (Astrodon 3 nm) on 2012-02-06 and 2012-02-09 using a QSI 583 from northern New Jersey through an Astro-Physics 155mm refractor at f7.1. North is up. ©2012

The Crab Nebula in hydrogen-alpha light.

8 hours through an Astrodon 3 nm H-a filter using a QSI 583 camera on 2012-02-06 and 2012-02-09 through an Astro-Physics 155mm refractor at f7.1 from northern New Jersey. North is up. ©2012