Knowledge Bank

Recent observations of Venus have provided spectra which show the $CO2$ bands from 7800 {\AA} to 12177 {\AA}. The bands near 1.2 microns have been impossible to photograph for several years because the only available infrared film (Kodak 1Z) is not sensitive beyond $\sim 11,500$ {\AA}. Two new methods are now available and they have enabled us to photograph the $CO2$ bands at $1.2\mu$. The first method is the two-stage RCA infrared image tube, developed with the support of, and kindly made available by, the Carnegie-NSF Image Tube Committee. The second method uses infrared film, T/0-106 which has a peak sensitivity at $1.05\mu$. Progressively longer exposure times are required at longer wavelengths, and for this reason we were unable to obtain the $CO2$ bands at $1.4\mu$ for Venus. Equivalent widths of individual rotational lines were measured for these bands and rotational temperatures were found for the Venus atmosphere.