"Until the last few years, all of the exploding stars in the Universe were thought to be of two types : core-collapse of a massive star or thermonuclear explosion of a white dwarf. The advent of wide-field synoptic sky surveys has opened up a new parameter space which allows very large volumes of the Universe to be searched for explosive stars. A new class of ""ultra-luminous"" supernovae have been discovered that challenge our physical understanding. These optical transients are typically 20-100 times brighter than normal supernovae and the physical mechanism that produces their huge luminosity is not well understood. A proportion of them may be “pair-instability” supernovae, which have been predicted only to exist in the early Universe and result from the evolution of Population III metal free stars. The existence of this ultra-luminous population of explosions in the nearby Universe is now certain, but what their nature is and what fraction really are “pair-instability” supernovae remains to be determined. The Pan-STARRS is a novel wide-field synoptic telescope survey which sweeps the sky to find moving objects and optical transients. I have secured leadership roles in the survey which will allow me to quantify this population of ultra-luminous supernovae at low and high redshift and to uncover their true nature. This will pave the way for searching for them at the highest redshifts with future space missions, possibly pushing into the era of reonization at z ~ 6, and determining whether the first supernovae in the Universe can be observed. Theoretical calculations for the number of Population III supernovae (from the first stars) have predicted low numbers of detections. The recent surprising discovery that these pair-instability supernovae may exist in the local Universe, and appear confined to low-metallicity galaxies, could potentially alter these predictions dramatically."