The investigators will acquire high spectral resolution data from Balmer alpha and Balmer beta hydrogen emissions to determine hydrogen density profiles, fluxes, and effective temperatures in the upper atmosphere. The work is aimed at resolving long-standing observational difficulties in measuring the faint geocoronal emission lines in the night sky. The measurements will be obtained with a high-sensitivity Fabry-Perot interferometer, applying precise methods for obtaining accurate calibration of wavelengths and instrumental profiles, and for correcting for galactic background emissions and atmospheric transmission effects. The measurements will be combined with models to achieve a better understanding of the hydrogen geocorona which influences the chemistry of the upper atmosphere and is linked to long-term variations due to global change.
