Nasa prepares for the rare T Coronae Borealis explosion by September, a spectacular event occurring every 80 years in a binary star system. The Blaze Star's brightness increase will be visible without telescopes, resembling the North Star.Nasa prepares for the rare T Coronae Borealis explosion by September, a spectacular event occurring every 80 years in a binary star system. The Blaze Star's brightness increase will be visible without telescopes, resembling the North Star.