NGC 51
NGC 51 is a lenticular galaxy in the constellation Andromeda. It has a diameter of 90,000 light-years. The galaxy was discovered on September 7, 1885, by Lewis Swift, who described it as "Pretty faint, pretty small, round, brighter middle."
One supernova has been observed in NGC 51. SN 2016gxp, was discovered by POSS on October 5, 2016.