The O+ 834-¿ dayglow observations made with the EUV spectrometer on the Air Force satellite STP-78-1 are interpreted with use of a radiation transfer model. At 600-km altitude the dayglow intensity was observed to vary with magnetic latitude from 30 R to 300 R in the near zenith direction (0=40¿) and from 400 R to 500 R in the near nadir intensity ratio of 0.3--0.65 over much of the dayside indicates that the O+ ions in the topside ionosphere constitute an optically thick medium for resonance scattering of 834-¿ airglow emission even at this high altitude. Simultaneous measurements of the O+ density from the AE-E spacecraft at 460-km altitude near the equator are used to normalize the STP 78-1 airglow data. A g value of 1.1¿10-8 s-1 at zero optical depth is required for the ionization excitation of atomic oxygen leading to the production of O+ atoms in 4P state. The latitudinal distribution of O+ density derived from the 834-¿ airglow data shows a double peak (at ¿13¿ latitude) surrounding an equatorial trough, characteristic of the equatorial anomaly, at altitudes below 1000 km and a single peak at the magnetic equator above 1000 km. At high latitudes (>20¿) the O+ densities in the summer hemisphere are substantially lower than these in winter hemisphere.