Novas occur in binary star systems when one star dumps matter onto a companion white dwarf. As the matter piles up on the surface of the white dwarf it heats up, fuses, and explodes, producing a flash of light 50,000 to 100,000 times brighter than the sun. Despite their brightness, most novas are invisible to the unaided eye because they are so far away. Nova Delphini is a rare exception.
Backyard astronomers who wish to see this nova should point their GOTO telescopes to coordinates 20:23:30.7, +20:46:06 (J2000). More information and updates are available from Sky and Telescope.