Long-term Spectroscopic Observations of the Atmospheric Airglow by the Sloan Digital Sky Survey

Spectra of the atmospheric airglow, termed sky spectra, are collected to estimate the total amount of contamination present in science spectra, and are intended to be used in a sky subtraction process. The Sloan Digital Sky Survey (SDSS) and Baryon Oscillation Spectroscopic Survey (BOSS) are large astronomical data sets that have nearly continuously recorded sky spectra at latitude 32.78° N longitude 105.82° W over a duration of 14 years. With a bandpass from 3800 Å to 9200 Å, the BOSS and SDSS airglow spectra contain emission from atomic and molecular oxygen, atomic sodium, and the hydroxyl molecule. The BOSS and SDSS sky spectra are an invaluable long-term record of the variations in airglow emission. Using the BOSS and SDSS sky spectra an analysis of airglow temporal variations was performed. Airglow variations were examined on the three timescales of nightly, annual, and long-term. In this manner the amplitude of airglow temporal variations has been estimated. Coincident satellite observations of the atmospheric profiles in temperature, constituent concentrations, and airglow emissions from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument were also examined. The atmospheric profiles were used to gain a deeper understanding of the variations in airglow emission processes as they are observed by ground based astronomical instruments.