The Gum Nebula
Named for Australian astronomer Colin Stanley Gum (1924-1960), The Gum Nebula is so large
and close it is actually hard to see. In fact, we are only about 450 light-years from the front edge
and 1,500 light-years from the back edge of this cosmic cloud of glowing hydrogen gas. Covered
in this 41 degree-wide mosaic of H-alpha images, the faint emission region is otherwise easy to lose
against the background of Milky Way stars. The complex nebula is thought to be a supernova
remnant over a million years old, sprawling across the southern constellations Vela and Puppis.