Rapid changes of brightness in P/Halley

Scanner observations of the coma of periodic comet Encke (P/Encke) are presented for four nights in March 1984 during its post-perihelion period. The strong emission features of CN and C₂ molecules have been identified and the abundances of CN and C₂ are estimated. The production rates of these molecules have also been derived from their band luminosities. No trace of sodium emission has been found in this comet.