sentences:  The star was originally charted by the Romanian-American astronomer Nicholas Sanduleak in 1970, but remained just a number in a catalogue until identified as the star that exploded in the first naked eye supernova since the invention of the telescope, when it in maximum reached visual magnitude +2,8.The discovery that a blue supergiant was a supernova progenitor contradicted all known theories at the time and produced a flurry of new ideas about how such a thing might happen, but it is now accepted that blue supergiants are a normal progenitor for some supernovae.The candidate luminous blue variable HD 168625 possesses a bipolar nebula that is a close twin of that around Sk -69 202.