Spectroscopic observations of CH Cygni during the 1977 - 1978 outburst.

Spectroscopic observations, covering the region from 3500 to 8000 A, of the symbiotic star CH Cygni, obtained between June 1977 and December 1978, are reported. Emission lines of H, Fe II, He I, and forbidden Fe II were observed to vary in intensity, reaching maximum strength approximately 18 months after the initial photometric outburst. Radial velocities derived for the various elements show the effects of stratification within the circumstellar envelope. Apparent variations in the velocity of H-alpha are explained in terms of the observed intensity variations. The observations were found to be consistent with a model in which a single long-lived hot spot developes at irregular intervals and produces the observed outbursts.