Ultraviolet spectra of the tropical oxygen night-glow in the range of 830 to 1850 ¿ (in first order) at 3 ¿ resolution were obtained with the Hopkins Ultraviolet Telescope during the Astro-1 space shuttle mission in December 1990. We present here the data obtained on a setting celestial target as the zenith angle of the line-of-sight varied from 77 to 95 ¿C. The dominant features in the spectrum (other than geocoronal hydrogen) are OI&lgr;&lgr;1304 and 1356 and the radiative recombination continuum near 911 ¿. The continuum is resolved and found to be consistent with an electron temperature in the range 1000--1250 K. The observed ratio of the brightness of OI&lgr;1356 to the continuum suggests that O+-O- mutual neutralization contributes about 40% to the 1356 ¿ emission. The dependence of the optically thin emissions on zenith angle is consistent with a simple ionospheric model. Weak OI&lgr;989 emission is also detected, but there is no evidence for any similarly produced atomic nitrogen emissions. ¿ American Geophysical Union 1992