Redshift of the identification: proposed identification was discarded and the field shown to be obscured proposed identification was discarded and the field shown to be empty, or the preceding classification as an empty field was confirmed identification was confirmed by means of accurate radio and optical positions; or, in the case of a quasar, by measuring its UBV color photoelectrically identification was discarded on the basis of a better radio or optical position subsequent spectrum showed that proposed identification is really a QSO (quasar) subsequent spectrum showed that proposed identification is a star Code for confirmation or invalidation of the identification: Optical name for the identification: Identification number of the source in the Fourth Cambridge Radio Survey Catalogue (4C):