The combination of technological advances in wide-field digital cameras, powerful computing and proper multinational organisation now enable us to conduct surveys that monitor the sky in visible light in near-real time. This opens new opportunities in the study of stars exploding as supernovae. Very early observations of supernovae allow us to investigate the nature of supernova progenitor stars in new and powerful ways, and may even offer revolutionary clues about the physics of the explosion process itself. We can now regularly observe the cooling emission produced in the aftermath of the breakout of the explosion shock from the surface of the dying star, providing clues about the energetics of the explosions and the properties of the progenitor. A combination of UV observations from space with ground-based visible-light data is especially powerful. Recent spectroscopic observations obtained within hours of explosion ("flash specroscopy") revealed transients emission lines that trace compact distributions of circumstellar matter around exploding massive stars, providing evidence for stellar instabilities that occur months to years prior to the terminal explosion. Forthcoming ground (ZTF) and Space (ULTRASAT) surveys will continue to revolutionize this field.
Some recent highlights: