The average rotational temperature of the Cytherean atmosphere above the cloud tops was found to be Trot = 244 ± 10 K based on twelve plates of the 7883-Å CO2 band. If the temperatures found from the 7820-Å band on the same plate are averaged with the temperatures found from the 7883-Å band, we obtaina temperature of Trot = 245 ± 6 K. The observations of Venus were made between April and December of 1967. Laboratory measurements of the 7883-Å band are lacking, but we infer that the band is half as strong as the 7820-Å band.
L. D. Gray, R. A. Schorn, and E. Barker, "High Dispersion Spectroscopic Observation of Venus. IV: The Weak Carbon Dioxide Band at 7883 A," Appl. Opt. 8, 2087-2093 (1969)