A nova has flared up in the constellation Sagittarius, and it’s grown bright enough to see with the naked eye in the pre-dawn sky. As of this weekend, according to Sky and Telescope, the nova has reached an impressive magnitude 4.3 which is plenty bright enough to see without optical aid in clear sky. The flaring star has been officially named Nova Sagittarii 2015 No.2.
“Nova” is a pre-telescopic term which means “new star”, because a nova seems to appear in a place where no star appeared before.