The Type II supernova SN1987A which occurred in the LMC is the brightest and most completely observed supernova ever recorded. Objective prism and UBV observations were made of the blue supergiant progenitor Sanduleak −69°202 and indicate that the visual absorption lies in the range 0.4<AV<0.6. Furthermore, the distance to the LMC is known in absolute units with a precision of about ± 15% (m-M = 18.45, Feast 1988) which combined with the above data and subseguent photometric observations permits detailed comparison with theory.
Within 107 minutes of the Kamiokande 1MB neutrino event the region of the supernova was being observed by Albert Jones, although it was not until 0.8 days after the event that the supernova was officially discovered by Shelton. The first photoelectric observation was made at 1.1 days, by William Allen (1988) a New Zealand amateur. Other observations made during the first two days, have been conveniently tabulated by Arnett (1988). During this time the supernova steadily brightened in V, although theory predicts that it was rapidly fading bolometrically and cooling, after the intense heating that occurred when the shock wave reached the stellar surface about 3 hours after core collapse.