When a star goes supernova, it leaves a remnant, like the one Tycho Brahe observed in 1572, or Johannes Kepler in 1604.

FORBES: When A Supernova ... Fizzles

Mandel's particular obsession is imaging: using long exposures to make pictures of celestial bodies--like his shot of the Veil Nebula supernova remnant, which cannot be seen merely by gazing through a telescope.

FORBES: A Star Is Born