An article published in “The Astrophysical Journal” reports the observations of the supernova cataloged as SN 2020tlf, the first case in which astronomers observed a red supergiant star in the period immediately preceding the explosion. A team of researchers used the Pan-STARRS telescope in Hawaii to detect the changes taking place in the red supergiant in the summer of 2020 and then used the NIRES and DEIMOS instruments of the Keck Observatory, also in Hawaii, for the first spectrographic detections of the supernova emissions in the fall of 2020. Subsequently, other instruments added data on the supernova. Astronomers expected a red supergiant to go through a quiet period before exploding, but SN 2020tlf’s progenitor emitted strong radiation in the last year of its life.