Extreme ultraviolet observations of the latitudinal variation of helium

A recent review of rocket observations of the atomic helium resonance transition at 584 A (11S–21P) concluded that a self-consistent picture of the near and extraterrestrial radiation field (at this and other EUV wavelengths) could not be formed from a few observations under a wide variety of conditions [Meier and Weller, 1972]. With this in mind, a satellite experiment was conducted to map the global environment in the spectral band 150–1500 A over an extended period of time. Initial reports of the results from this experiment have been given by Weller and Meier [1973] and Meier and Weller [1973]. In the companion paper [Weller and Meier, 1974], observational and experimental details are described along with data on the He+ 304-A emission.