Observations of far and extreme ultraviolet OI emissions in tropical ionosphere

The first observations of equatorial ionospheric emissions in the 800–1050 Å spectral region have been made from the STP 72-1 satellite. Analysis of these data and comparison with data taken simultaneously in the 1220–1400 Å wavelength range indicate a strong correlation between these emissions, as well as a pronounced dependence on season and dip latitude. Both nadir data and spin data are presented, and analyses of spin data indicate latitudinal variations of the F 2 peak altitude. Theoretical calculations of emission in the 800–1050 Å spectral region show that the data are consistent with radiative recombination of O + as a source of the observed emissions.