Atmosphere explorer observations of the geocoronal H balmer α nightglow

The Balmer α nightglow emission of geocoronal atomic hydrogen has been investigated using photometric data obtained by the Visible Airglow Experiment on board the Atmosphere Explorer E satellite. The measured H Balmer α intensities are presented as a function of solar depression angle, observation zenith angle, and azimuth relative to the Sun for solar minimum conditions. The results are at variance with the earlier D2A satellite observations but in better agreement with previous ground-based studies. As a result of a comparison with theoretical predictions, the present observations reaffirm the findings of the ground-based investigations in implying that values for the Lyman β line center flux are a factor of 2 greater than those derived from direct measurements