This experiment provided detailed data on the rates of excitation of the atomic and
molecular constituents of the thermosphere. The wavelength range, expressed in Angstroms, was measured
in pairs: 7319 and 6563, 5300 and dark, 5577 and 7319, 2800 and 5200, 6300 and 5577, calibrate and
2800, and 6563 and 6300. A photometer was used which contained two separate optical channels, a narrow
field of view and a wide field of view. Spectral selection was accomplished with a filter wheel that
contained six interference filters and a dark and calibrate position. The two channels were separated
by 90 deg. One channel had a 3-deg half-angle cone field of view for high sensitivity and pointed
normally toward the local zenith. The second had a field of view of 0.75-deg half cone for high spatial
resolution, pointing tangentially to the surface of the earth when the satellite was in the oriented
mode. Both channels were protected from stray light contamination during the daytime with multistage
baffle systems. Filters were operated in several modes. The two separate optical channels were monitored
at time intervals consistent with their angular resolution in the spinning mode. More experiment details
can be found in P. B. Hays et al., Radio Sci., v. 8, n. 4, p. 369, 1973.