Because quasars were not recognized until 1963,[3] the nature of this object was unknown when it was first noted in a 1957 survey of faint blue stars (mainly white dwarfs) that lie away from the plane of the Milky Way. On photographic plates taken with the 0.7m Schmidt telescope at the Tonantzintla Observatory in Mexico, it appeared "decidedly violet" and was listed as number 618 in the Tonantzintla catalogue.[4]